diff --git a/app/Console/Commands/UpdateExpiryDate.php b/app/Console/Commands/UpdateExpiryDate.php
new file mode 100644
index 0000000..743c0b7
--- /dev/null
+++ b/app/Console/Commands/UpdateExpiryDate.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace App\Console\Commands;
+
+use App\Models\OrderItem;
+use Carbon\Carbon;
+use Illuminate\Console\Command;
+
+class UpdateExpiryDate extends Command
+{
+    protected $signature = 'app:update-expiry-date {--dry-run : Show what would be updated without making changes}';
+
+    protected $description = 'Update expiry_date for existing order items based on created_at + months';
+
+    public function handle()
+    {
+        $dryRun = $this->option('dry-run');
+        
+        $query = OrderItem::whereNull('expiry_date')
+            ->whereNotNull('months')
+            ->where('months', '>', 0);
+
+        $count = $query->count();
+
+        if ($count === 0) {
+            $this->info('No order items need to be updated.');
+            return 0;
+        }
+
+        $this->info("Found {$count} order items to update.");
+
+        if ($dryRun) {
+            $this->warn('DRY RUN - No changes will be made.');
+            $query->chunk(100, function ($items) {
+                foreach ($items as $item) {
+                    $expiryDate = Carbon::parse($item->created_at)->addMonths($item->months);
+                    $this->line("Order #{$item->order_id}, Item #{$item->id}: would set expiry_date to {$expiryDate}");
+                }
+            });
+        } else {
+            $updated = 0;
+            $query->chunk(100, function ($items) use (&$updated) {
+                foreach ($items as $item) {
+                    $expiryDate = Carbon::parse($item->created_at)->addMonths($item->months);
+                    $item->update(['expiry_date' => $expiryDate]);
+                    $updated++;
+                }
+            });
+            $this->info("Updated {$updated} order items.");
+        }
+
+        return 0;
+    }
+}
diff --git a/app/Http/Controllers/Api/Admin/Order/OrderController.php b/app/Http/Controllers/Api/Admin/Order/OrderController.php
index 5d1e874..2739d32 100644
--- a/app/Http/Controllers/Api/Admin/Order/OrderController.php
+++ b/app/Http/Controllers/Api/Admin/Order/OrderController.php
@@ -22,11 +22,13 @@ use App\Repositories\Module\Vmware\VmwareRepositoryInterface;
 use App\Repositories\Order\OrderRepositoryInterface;
 use App\Repositories\Os\OsRepositoryInterface;
 use App\Repositories\VPS\VPSRepositoryInterface;
+use App\Models\Customer;
 use Carbon\Carbon;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Auth;
 use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Storage;
 use Illuminate\Support\Facades\Validator;
 use Yajra\DataTables\Facades\DataTables;
 
@@ -95,6 +97,14 @@ class OrderController extends Controller
     {
         $request->validated();
 
+        $customer = Customer::find($request->customer_id);
+        if (!$customer || (int) $customer->status !== 1) {
+            return response()->json([
+                'error'   => true,
+                'message' => 'Tài khoản khách hàng không hoạt động. Không thể tạo đơn hàng.',
+            ], 422);
+        }
+
         $total = 0;
         $product_item = [];
         $relid_data = [];
@@ -167,28 +177,32 @@ class OrderController extends Controller
             $total += $item['quantity'] * ($item['price_custom'] ?? ($product->price_sale ?? $product->price)) * $billingDetails['billing'];
         }
 
+        $paymentRecord = \App\Models\Payment::find((int) $request->payment_method);
+        $isBankTransfer = $paymentRecord && (int) $paymentRecord->type === 1;
+
         $order_item = [
-            'order_num' => Helper::generateUniqueCode(),
-            'customer_id' => $request->customer_id,
-            'invoice_id' => 0,
-            'discount_id' => $request->discount_id ?: null,
-            'amount' => $total + ($total * (10 / 100)),
-            'payment_method' => $request->payment_method,
-            'user_id' => Auth::guard('admin')->id(),
-            'status' => $request->status,
-            'client_ip' => $request->getClientIp()
+            'order_num'    => Helper::generateUniqueCode(),
+            'customer_id'  => $request->customer_id,
+            'invoice_id'   => 0,
+            'discount_id'  => $request->discount_id ?: null,
+            'amount'       => $total + ($total * (10 / 100)),
+            'payment_id'   => $paymentRecord?->id,
+            'payment_proof' => $request->payment_proof ?? null,
+            'user_id'      => Auth::guard('admin')->id(),
+            'status'       => $request->status,
+            'client_ip'    => $request->getClientIp(),
         ];
 
         $invoice_data = [
-            'date' => Carbon::today()->toDateString(),
-            'due_date' => Carbon::today()->toDateString(),
-            'date_paid' => (int)$request->status === 1 ? Carbon::today()->toDateString() : null,
-            'sub_total' => $total,
-            'tax' => $total * (10 / 100),
-            'total' => $total + ($total * (10 / 100)),
-            'payment_method' => $request->payment_method,
+            'date'       => Carbon::today()->toDateString(),
+            'due_date'   => Carbon::today()->toDateString(),
+            'date_paid'  => (int)$request->status === 1 ? Carbon::today()->toDateString() : null,
+            'sub_total'  => $total,
+            'tax'        => $total * (10 / 100),
+            'total'      => $total + ($total * (10 / 100)),
+            'payment_id' => $paymentRecord?->id,
             'customer_id' => $request->create_invoice ? $request->customer_id : 0,
-            'status' => $request->status
+            'status'     => $request->status
         ];
 
         DB::beginTransaction();
@@ -242,30 +256,39 @@ class OrderController extends Controller
             $this->invoiceItemRepository->insert($invoiceItemData);
 
             $now = now();
-            \App\Models\OrderItem::insert(array_map(fn($item) => [
-                'order_id'      => $order->id,
-                'product_id'    => $item['product_id'],
-                'billing_cycle' => $item['billing_cycle'],
-                'months'        => $item['months'],
-                'os_id'         => $item['os_id'],
-                'quantity'      => $item['quantity'],
-                'server_name'   => $item['server_name'],
-                'price'         => $item['price'],
-                'created_at'    => $now,
-                'updated_at'    => $now,
-            ], $product_item));
+            \App\Models\OrderItem::insert(array_map(function ($item) use ($now) {
+                $expiryDate = $now->copy()->addMonths($item['months']);
+                return [
+                    'order_id'      => $order->id,
+                    'product_id'    => $item['product_id'],
+                    'billing_cycle' => $item['billing_cycle'],
+                    'months'        => $item['months'],
+                    'expiry_date'   => $expiryDate,
+                    'os_id'         => $item['os_id'],
+                    'quantity'      => $item['quantity'],
+                    'server_name'   => $item['server_name'],
+                    'price'         => $item['price'],
+                    'created_at'    => $now,
+                    'updated_at'    => $now,
+                ];
+            }, $product_item));
 
             // Dispatch VM creation job for VPS/cloud products
             $vpsTypes = ['vps', 'cloud'];
             $createdOrderItems = \App\Models\OrderItem::where('order_id', $order->id)->get();
             foreach ($createdOrderItems as $orderItem) {
-                $pt = $orderItem->product?->product_type ?? $orderItem->billing_cycle;
                 if (in_array($orderItem->product?->product_type, $vpsTypes)) {
                     \App\Jobs\VirtualMachine\Create\CreateVirtualMachineJob::dispatch($orderItem)
                         ->delay(now()->addSeconds(10));
                 }
             }
 
+            // Deduct customer balance for non-bank-transfer payments
+            if (!$isBankTransfer) {
+                Customer::where('id', $request->customer_id)
+                    ->decrement('total', (int) ($total + ($total * (10 / 100))));
+            }
+
             DB::commit();
 
             return response()->json([
@@ -284,10 +307,15 @@ class OrderController extends Controller
 
     public function show(int $id): JsonResponse
     {
-        $order = $this->orderRepository->findWithRelationships(
-            $id, 
-            ['orderItem', 'user', 'customer.invoiceItem.type', 'payment', 'discount', 'invoice.invoiceItem']
-        );
+        $order = Order::with([
+            'orderItems.product', 
+            'orderItems.os',
+            'user', 
+            'customer', 
+            'payment', 
+            'discount', 
+            'invoice'
+        ])->find($id);
 
         if (!$order) {
             return response()->json([
@@ -501,6 +529,19 @@ class OrderController extends Controller
         }
     }
 
+    public function uploadProof(Request $request): JsonResponse
+    {
+        $request->validate(['file' => 'required|image|max:5120']);
+
+        $path = $request->file('file')->store('payment-proofs', 'public');
+
+        return response()->json([
+            'error' => false,
+            'url'   => Storage::disk('public')->url($path),
+            'path'  => $path,
+        ]);
+    }
+
     private function calculateBillingDetails($billing): array
     {
         $months = match ($billing) {
diff --git a/app/Http/Controllers/Api/Admin/OsManager/OsController.php b/app/Http/Controllers/Api/Admin/OsManager/OsController.php
new file mode 100644
index 0000000..7ad38e9
--- /dev/null
+++ b/app/Http/Controllers/Api/Admin/OsManager/OsController.php
@@ -0,0 +1,90 @@
+<?php
+
+namespace App\Http\Controllers\Api\Admin\OsManager;
+
+use App\Http\Controllers\Controller;
+use App\Models\Os;
+use App\Models\OsGroup;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+
+class OsController extends Controller
+{
+    public function store(Request $request): JsonResponse
+    {
+        $validated = $request->validate([
+            'version'     => 'required|string|max:100',
+            'os_group_id' => 'required|integer|exists:os_group,id',
+            'template_id' => 'nullable|string|max:255',
+            'is_active'   => 'boolean',
+        ]);
+
+        $os = Os::create([
+            'version'     => $validated['version'],
+            'os_group_id' => $validated['os_group_id'],
+            'template_id' => $validated['template_id'] ?? null,
+            'status'      => ($validated['is_active'] ?? true) ? 1 : 0,
+        ]);
+
+        return response()->json([
+            'error'   => false,
+            'message' => 'Thêm OS thành công.',
+            'data'    => $this->formatOs($os),
+        ], 201);
+    }
+
+    public function update(Request $request, int $id): JsonResponse
+    {
+        $os = Os::find($id);
+
+        if (! $os) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy OS.'], 404);
+        }
+
+        $validated = $request->validate([
+            'version'     => 'sometimes|required|string|max:100',
+            'os_group_id' => 'sometimes|integer|exists:os_group,id',
+            'template_id' => 'nullable|string|max:255',
+            'is_active'   => 'boolean',
+        ]);
+
+        $os->update([
+            'version'     => $validated['version']     ?? $os->version,
+            'os_group_id' => $validated['os_group_id'] ?? $os->os_group_id,
+            'template_id' => array_key_exists('template_id', $validated) ? $validated['template_id'] : $os->template_id,
+            'status'      => isset($validated['is_active']) ? ($validated['is_active'] ? 1 : 0) : $os->status,
+        ]);
+
+        return response()->json([
+            'error'   => false,
+            'message' => 'Cập nhật OS thành công.',
+            'data'    => $this->formatOs($os->fresh()),
+        ]);
+    }
+
+    public function destroy(int $id): JsonResponse
+    {
+        $os = Os::find($id);
+
+        if (! $os) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy OS.'], 404);
+        }
+
+        $os->delete();
+
+        return response()->json(['error' => false, 'message' => 'Xoá OS thành công.']);
+    }
+
+    // ── helpers ──────────────────────────────────────────────────────────────
+
+    private function formatOs(Os $os): array
+    {
+        return [
+            'id'          => $os->id,
+            'version'     => $os->version,
+            'template_id' => $os->template_id,
+            'is_active'   => (bool) $os->status,
+            'os_group_id' => $os->os_group_id,
+        ];
+    }
+}
diff --git a/app/Http/Controllers/Api/Admin/OsManager/OsGroupController.php b/app/Http/Controllers/Api/Admin/OsManager/OsGroupController.php
new file mode 100644
index 0000000..09c3204
--- /dev/null
+++ b/app/Http/Controllers/Api/Admin/OsManager/OsGroupController.php
@@ -0,0 +1,152 @@
+<?php
+
+namespace App\Http\Controllers\Api\Admin\OsManager;
+
+use App\Http\Controllers\Controller;
+use App\Models\OsGroup;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+
+class OsGroupController extends Controller
+{
+    /**
+     * List all OS groups with their OS entries.
+     * Supports ?all=true for full list (no pagination).
+     */
+    public function index(Request $request): JsonResponse
+    {
+        $query = OsGroup::withCount('os')
+            ->with(['os' => fn($q) => $q->orderBy('version')])
+            ->when(
+                $request->get('filter'),
+                fn($q, $f) => $q->where('name', 'like', "%{$f}%")
+            )
+            ->orderBy('name');
+
+        if ($request->boolean('all')) {
+            $items = $query->get();
+
+            return response()->json([
+                'error' => false,
+                'data'  => $items->map(fn($g) => $this->formatGroup($g)),
+            ]);
+        }
+
+        $perPage   = min((int) $request->get('per_page', 15), 100);
+        $paginator = $query->paginate($perPage);
+
+        return response()->json([
+            'error' => false,
+            'data'  => [
+                'items'        => collect($paginator->items())->map(fn($g) => $this->formatGroup($g)),
+                'total'        => $paginator->total(),
+                'per_page'     => $paginator->perPage(),
+                'current_page' => $paginator->currentPage(),
+                'last_page'    => $paginator->lastPage(),
+            ],
+        ]);
+    }
+
+    public function show(int $id): JsonResponse
+    {
+        $group = OsGroup::withCount('os')
+            ->with(['os' => fn($q) => $q->orderBy('version')])
+            ->find($id);
+
+        if (! $group) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy nhóm OS.'], 404);
+        }
+
+        return response()->json(['error' => false, 'data' => $this->formatGroup($group)]);
+    }
+
+    public function store(Request $request): JsonResponse
+    {
+        $validated = $request->validate([
+            'name'      => 'required|string|max:255',
+            'is_active' => 'boolean',
+        ]);
+
+        $group = OsGroup::create([
+            'name'   => $validated['name'],
+            'status' => ($validated['is_active'] ?? true) ? 1 : 0,
+        ]);
+
+        return response()->json([
+            'error'   => false,
+            'message' => 'Tạo nhóm OS thành công.',
+            'data'    => $this->formatGroup($group->load('os')),
+        ], 201);
+    }
+
+    public function update(Request $request, int $id): JsonResponse
+    {
+        $group = OsGroup::find($id);
+
+        if (! $group) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy nhóm OS.'], 404);
+        }
+
+        $validated = $request->validate([
+            'name'      => 'sometimes|required|string|max:255',
+            'is_active' => 'boolean',
+        ]);
+
+        $group->update([
+            'name'   => $validated['name'] ?? $group->name,
+            'status' => isset($validated['is_active']) ? ($validated['is_active'] ? 1 : 0) : $group->status,
+        ]);
+
+        return response()->json([
+            'error'   => false,
+            'message' => 'Cập nhật nhóm OS thành công.',
+            'data'    => $this->formatGroup($group->fresh(['os'])),
+        ]);
+    }
+
+    public function destroy(int $id): JsonResponse
+    {
+        $group = OsGroup::withCount('os')->find($id);
+
+        if (! $group) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy nhóm OS.'], 404);
+        }
+
+        if ($group->os_count > 0) {
+            return response()->json([
+                'error'   => true,
+                'message' => "Không thể xoá nhóm đang chứa {$group->os_count} OS. Hãy xoá các OS trước.",
+            ], 422);
+        }
+
+        $group->delete();
+
+        return response()->json(['error' => false, 'message' => 'Xoá nhóm OS thành công.']);
+    }
+
+    // ── helpers ──────────────────────────────────────────────────────────────
+
+    private function formatGroup(OsGroup $group): array
+    {
+        return [
+            'id'        => $group->id,
+            'name'      => $group->name,
+            'is_active' => (bool) $group->status,
+            'os_count'  => $group->os_count ?? $group->os->count(),
+            'os_list'   => $group->relationLoaded('os')
+                ? $group->os->map(fn($o) => $this->formatOs($o))->values()
+                : [],
+        ];
+    }
+
+    private function formatOs(\App\Models\Os $os): array
+    {
+        return [
+            'id'          => $os->id,
+            'version'     => $os->version,
+            'template_id' => $os->template_id,
+            'is_active'   => (bool) $os->status,
+            'os_group_id' => $os->os_group_id,
+        ];
+    }
+}
diff --git a/app/Http/Controllers/Api/Admin/Payment/PaymentController.php b/app/Http/Controllers/Api/Admin/Payment/PaymentController.php
index 5441533..06901a0 100644
--- a/app/Http/Controllers/Api/Admin/Payment/PaymentController.php
+++ b/app/Http/Controllers/Api/Admin/Payment/PaymentController.php
@@ -26,6 +26,21 @@ class PaymentController extends Controller
         ]);
     }
 
+    public function forSelect(): JsonResponse
+    {
+        $payments = $this->paymentRepository->filter(['status' => 1]);
+
+        return response()->json([
+            'error' => false,
+            'data'  => $payments->map(fn($p) => [
+                'id'     => $p->id,
+                'name'   => $p->name,
+                'type'   => (int) $p->type,
+                'status' => (int) $p->status,
+            ])->values(),
+        ]);
+    }
+
     public function store(PaymentRequest $request): JsonResponse
     {
         $request->validated();
diff --git a/app/Http/Controllers/Api/Admin/Product/ProductController.php b/app/Http/Controllers/Api/Admin/Product/ProductController.php
index 8d1cfd4..986d7f5 100644
--- a/app/Http/Controllers/Api/Admin/Product/ProductController.php
+++ b/app/Http/Controllers/Api/Admin/Product/ProductController.php
@@ -6,6 +6,7 @@ use App\Http\Controllers\Controller;
 use App\Http\Resources\Api\Admin\ProductResource;
 use App\Models\Product;
 use App\Repositories\Admin\Product\AdminProductRepositoryInterface;
+use App\Models\Os;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Str;
@@ -44,6 +45,9 @@ class ProductController extends Controller
             return response()->json(['error' => true, 'message' => 'Không tìm thấy sản phẩm.'], 404);
         }
 
+        // Load operatingSystems relationship (product_os table)
+        $product->load('operatingSystems');
+
         return response()->json([
             'error' => false,
             'data'  => new ProductResource($product),
@@ -105,11 +109,13 @@ class ProductController extends Controller
             'product_categories_id' => 'nullable|integer|exists:product_categories,id',
             'product_type'          => 'nullable|string',
             'is_active'             => 'boolean',
-            'setup_fee'              => 'nullable|numeric|min:0',
-            'cpu'                    => 'nullable|numeric|min:0',
-            'ram'                    => 'nullable|numeric|min:0',
-            'disk'                   => 'nullable|numeric|min:0',
-            'bandwidth'              => 'nullable|numeric|min:0',
+            'setup_fee'             => 'nullable|numeric|min:0',
+            'cpu'                   => 'nullable|numeric|min:0',
+            'ram'                   => 'nullable|numeric|min:0',
+            'disk'                  => 'nullable|numeric|min:0',
+            'bandwidth'             => 'nullable|numeric|min:0',
+            'os_ids'                => 'nullable|array',
+            'os_ids.*'              => 'integer|exists:os,id',
         ]);
 
         if (isset($validated['name']) && $validated['name'] !== $product->name) {
@@ -121,8 +127,17 @@ class ProductController extends Controller
             $validated['product_type'] = $category?->type;
         }
 
+        // Handle OS associations via product_os table
+        $osIds = $validated['os_ids'] ?? null;
+        unset($validated['os_ids']);
+
         $product->update($validated);
 
+        // Sync OS associations in product_os table
+        if ($osIds !== null) {
+            $product->operatingSystems()->sync($osIds);
+        }
+
         return response()->json([
             'error'   => false,
             'message' => 'Cập nhật sản phẩm thành công.',
@@ -151,7 +166,7 @@ class ProductController extends Controller
         $product = Product::find($id);
 
         if (!$product) {
-            return response()->json(['error' => true, 'message' => 'Không tìm thấy sản phẩm.'], 404);
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy sản phờng trình.'], 404);
         }
 
         $osList = $product->osVersions()
@@ -171,4 +186,49 @@ class ProductController extends Controller
             'data'  => $osList,
         ]);
     }
+
+    public function getOsList(): JsonResponse
+    {
+        $osList = Os::with('osGroup')
+            ->where('status', 1)
+            ->get()
+            ->map(fn($os) => [
+                'id'             => $os->id,
+                'name'           => $os->name,
+                'version'        => $os->version,
+                'os_group_name'  => $os->osGroup?->name,
+                'template_id'    => $os->template_id,
+            ]);
+
+        return response()->json([
+            'error' => false,
+            'data'  => $osList,
+        ]);
+    }
+
+    public function getOperatingSystems(int $id): JsonResponse
+    {
+        $product = Product::find($id);
+
+        if (!$product) {
+            return response()->json(['error' => true, 'message' => 'Không tìm thấy sản phẩm.'], 404);
+        }
+
+        $osList = $product->operatingSystems()
+            ->with('osGroup')
+            ->where('status', 1)
+            ->get()
+            ->map(fn($os) => [
+                'id'             => $os->id,
+                'name'           => $os->name,
+                'version'        => $os->version,
+                'os_group_name'  => $os->osGroup?->name,
+                'template_id'    => $os->template_id,
+            ]);
+
+        return response()->json([
+            'error' => false,
+            'data'  => $osList,
+        ]);
+    }
 }
diff --git a/app/Http/Requests/OrderRequest.php b/app/Http/Requests/OrderRequest.php
index 95907b3..71744b9 100644
--- a/app/Http/Requests/OrderRequest.php
+++ b/app/Http/Requests/OrderRequest.php
@@ -23,7 +23,7 @@ class OrderRequest extends FormRequest
     {
         return [
             'customer_id' => 'required',
-            'payment_method' => 'required',
+            'payment_method' => 'required|integer|min:1',
             'status' => 'required',
             'product.*.product_id' => 'required|numeric|not__in:0',
             'product.*.os_id'     => 'nullable|integer',
diff --git a/app/Http/Resources/Api/Admin/OrderResource.php b/app/Http/Resources/Api/Admin/OrderResource.php
index b9d246d..48aa0cd 100644
--- a/app/Http/Resources/Api/Admin/OrderResource.php
+++ b/app/Http/Resources/Api/Admin/OrderResource.php
@@ -10,17 +10,71 @@ class OrderResource extends JsonResource
     public function toArray(Request $request): array
     {
         return [
-            'id'        => $this->id,
+            'id' => $this->id,
             'order_num' => $this->order_num,
-            'customer'  => $this->whenLoaded('customer', fn() => [
+            'customer' => $this->whenLoaded('customer', fn() => [
                 'id'       => $this->customer->id,
                 'fullname' => $this->customer->fullname,
                 'email'    => $this->customer->email,
+                'phone' => $this->customer->phone ?? null,
             ]),
-            'amount'     => $this->amount,
-            'status'     => $this->status,
-            'date'       => $this->date,
+            'user' => $this->whenLoaded('user', fn() => [
+                'id' => $this->user->id,
+                'firstname' => $this->user->firstname,
+                'lastname' => $this->user->lastname,
+                'email' => $this->user->email,
+            ]),
+            'payment' => $this->whenLoaded('payment', fn() => [
+                'id' => $this->payment->id,
+                'name' => $this->payment->name,
+                'type' => $this->payment->type,
+            ]),
+            'discount' => $this->whenLoaded('discount', fn() => [
+                'id' => $this->discount->id,
+                'code' => $this->discount->code,
+                'value' => $this->discount->value,
+            ]),
+            'invoice' => $this->whenLoaded('invoice', fn() => [
+                'id' => $this->invoice->id,
+                'order_num' => $this->invoice->order_num,
+                'sub_total' => $this->invoice->sub_total,
+                'tax' => $this->invoice->tax,
+                'total' => $this->invoice->total,
+                'status' => $this->invoice->status,
+                'date' => $this->invoice->date,
+                'due_date' => $this->invoice->due_date,
+                'date_paid' => $this->invoice->date_paid,
+            ]),
+            'amount' => $this->amount,
+            'payment_method' => $this->whenLoaded('payment', fn() => $this->payment->name),
+            'payment_proof' => $this->payment_proof,
+            'note' => $this->note,
+            'client_ip' => $this->client_ip,
+            'status' => $this->status,
+            'date' => $this->date,
             'created_at' => $this->created_at,
+            'updated_at' => $this->updated_at,
+            'order_items' => $this->whenLoaded('orderItems', fn() => $this->orderItems->map(function ($item) {
+                return [
+                    'id' => $item->id,
+                    'product' => $item->product ? [
+                        'id' => $item->product->id,
+                        'name' => $item->product->name,
+                        'product_type' => $item->product->product_type,
+                    ] : null,
+                    'os' => $item->os ? [
+                        'id' => $item->os->id,
+                        'name' => $item->os->name,
+                        'version' => $item->os->version,
+                    ] : null,
+                    'billing_cycle' => $item->billing_cycle,
+                    'months' => $item->months,
+                    'expiry_date' => $item->expiry_date,
+                    'quantity' => $item->quantity,
+                    'server_name' => $item->server_name,
+                    'price' => $item->price,
+                ];
+            })),
         ];
     }
 }
diff --git a/app/Http/Resources/Api/Admin/ProductResource.php b/app/Http/Resources/Api/Admin/ProductResource.php
index a295171..316d6eb 100644
--- a/app/Http/Resources/Api/Admin/ProductResource.php
+++ b/app/Http/Resources/Api/Admin/ProductResource.php
@@ -13,6 +13,10 @@ class ProductResource extends JsonResource
             return $this->pricings->min('price');
         });
 
+        $osIds = $this->whenLoaded('operatingSystems', function () {
+            return $this->operatingSystems->pluck('id')->toArray();
+        });
+
         return [
             'id'           => $this->id,
             'uuid'         => $this->uuid,
@@ -30,6 +34,7 @@ class ProductResource extends JsonResource
             'min_price'    => $minPrice,
             'is_active'    => $this->is_active,
             'created_at'   => $this->created_at,
+            'os_ids'       => $osIds,
         ];
     }
 
diff --git a/app/Models/Order.php b/app/Models/Order.php
index 1c10913..5bc8292 100644
--- a/app/Models/Order.php
+++ b/app/Models/Order.php
@@ -46,7 +46,7 @@ class Order extends Model
 
     public function payment()
     {
-        return $this->belongsTo(\App\Models\Payment::class);
+        return $this->belongsTo(\App\Models\Payment::class, 'payment_method', 'id');
     }
 
     public function user()
@@ -56,7 +56,7 @@ class Order extends Model
 
     public function orderItem()
     {
-        return $this->belongsToMany(\App\Models\InvoiceItem::class, 'order__order_item', 'order_id', 'invoice_item_id');
+        return $this->belongsToMany(\App\Models\InvoiceItem::class, 'order_items', 'order_id', 'invoice_item_id');
     }
 
     public function orderItems()
diff --git a/app/Models/OrderItem.php b/app/Models/OrderItem.php
index 4b88bbd..40c20c1 100644
--- a/app/Models/OrderItem.php
+++ b/app/Models/OrderItem.php
@@ -9,9 +9,10 @@ class OrderItem extends Model
 {
     use HasFactory;
 
-    protected $table = 'order__order_item';
+    protected $table = 'order_items';
     protected $guarded = [];
     public $timestamps = false;
+    
     public function order()
     {
         return $this->belongsTo(Order::class, 'order_id');
diff --git a/app/Models/Payment.php b/app/Models/Payment.php
index a6bd450..e19d5f5 100644
--- a/app/Models/Payment.php
+++ b/app/Models/Payment.php
@@ -24,6 +24,10 @@ class Payment extends Model
     {
         return $this->belongsTo(\App\Models\Invoice::class);
     }
+    public function order()
+    {
+        return $this->belongsTo(\App\Models\Order::class);
+    }
     public function getStatus()
     {
         return match ($this->attributes['status']) {
diff --git a/app/Models/Product.php b/app/Models/Product.php
index cc46a80..6b4bc6d 100644
--- a/app/Models/Product.php
+++ b/app/Models/Product.php
@@ -75,6 +75,15 @@ class Product extends Model
             ->withTimestamps();
     }
 
+    /**
+     * Relationship: Product has many OS via product_os table (VPS OS selection)
+     */
+    public function operatingSystems()
+    {
+        return $this->belongsToMany(Os::class, 'product_os', 'product_id', 'os_id')
+            ->withTimestamps();
+    }
+
     /**
      * Relationship: Product has many Control Panels (for Hosting)
      */
diff --git a/database/migrations/2026_03_11_000002_add_payment_proof_to_order_table.php b/database/migrations/2026_03_11_000002_add_payment_proof_to_order_table.php
new file mode 100644
index 0000000..2d79eef
--- /dev/null
+++ b/database/migrations/2026_03_11_000002_add_payment_proof_to_order_table.php
@@ -0,0 +1,21 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration {
+    public function up(): void
+    {
+        Schema::table('order', function (Blueprint $table) {
+            $table->string('payment_proof')->nullable()->after('payment_method');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('order', function (Blueprint $table) {
+            $table->dropColumn('payment_proof');
+        });
+    }
+};
diff --git a/database/migrations/2026_03_11_144540_rename_order_items_table.php b/database/migrations/2026_03_11_144540_rename_order_items_table.php
new file mode 100644
index 0000000..de2224c
--- /dev/null
+++ b/database/migrations/2026_03_11_144540_rename_order_items_table.php
@@ -0,0 +1,24 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::rename('order__order_item', 'order_items');
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::rename('order_items', 'order__order_item');
+    }
+};
diff --git a/database/migrations/2026_03_11_153935_add_expiry_date_to_order_items_table.php b/database/migrations/2026_03_11_153935_add_expiry_date_to_order_items_table.php
new file mode 100644
index 0000000..135a1ee
--- /dev/null
+++ b/database/migrations/2026_03_11_153935_add_expiry_date_to_order_items_table.php
@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->timestamp('expiry_date')->nullable()->after('months');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->dropColumn('expiry_date');
+        });
+    }
+};
diff --git a/database/seeders/BankTransferPaymentSeeder.php b/database/seeders/BankTransferPaymentSeeder.php
new file mode 100644
index 0000000..3557fd8
--- /dev/null
+++ b/database/seeders/BankTransferPaymentSeeder.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Database\Seeders;
+
+use Illuminate\Database\Seeder;
+use Illuminate\Support\Facades\DB;
+
+class BankTransferPaymentSeeder extends Seeder
+{
+    public function run(): void
+    {
+        $methods = [
+            [
+                'name' => 'Số dư tài khoản',
+                'type' => 0,
+                'accountNo' => '',
+                'bankName' => '',
+                'bankCode' => '',
+                'logo' => '',
+                'status' => 1,
+            ],
+            [
+                'name' => 'Chuyển khoản ngân hàng',
+                'type' => 1,
+                'accountNo' => '',
+                'bankName' => '',
+                'bankCode' => '',
+                'logo' => '',
+                'status' => 1,
+            ],
+            [
+                'name' => 'Chuyển khoản VNPAY',
+                'type' => 1,
+                'accountNo' => '',
+                'bankName' => 'VNPAY',
+                'bankCode' => 'VNPAY',
+                'logo' => '',
+                'status' => 1,
+            ],
+            [
+                'name' => 'Chuyển khoản ACB',
+                'type' => 1,
+                'accountNo' => '',
+                'bankName' => 'Ngân hàng ACB',
+                'bankCode' => 'ACB',
+                'logo' => '',
+                'status' => 1,
+            ],
+            [
+                'name' => 'Chuyển khoản MB',
+                'type' => 1,
+                'accountNo' => '',
+                'bankName' => 'Ngân hàng MB',
+                'bankCode' => 'MB',
+                'logo' => '',
+                'status' => 1,
+            ],
+        ];
+
+        foreach ($methods as $method) {
+            DB::table('payment')
+                ->where('name', $method['name'])
+                ->exists() ?: DB::table('payment')->insert(array_merge($method, [
+                            'created_at' => now(),
+                            'updated_at' => now(),
+                        ]));
+        }
+    }
+}
diff --git a/routes/api.php b/routes/api.php
index 3d1aa91..7afc416 100644
--- a/routes/api.php
+++ b/routes/api.php
@@ -15,6 +15,8 @@ use App\Http\Controllers\Api\Admin\VPS\VPSController;
 use App\Http\Controllers\Api\Admin\VCenter\VCenterController;
 use App\Http\Controllers\Api\Admin\DnsManager\ServerController as DnsServerController;
 use App\Http\Controllers\Api\Admin\DnsManager\DomainController as DnsDomainController;
+use App\Http\Controllers\Api\Admin\OsManager\OsGroupController;
+use App\Http\Controllers\Api\Admin\OsManager\OsController;
 use App\Http\Services\Media;
 use App\Http\Services\vCenter as ServiceVCenter;
 use App\Models\ModuleVmware;
@@ -92,8 +94,13 @@ Route::prefix('v1')
                     Route::get('/',    [ProductController::class, 'index'])->middleware('perm:product-service.view');
                     Route::post('/',   [ProductController::class, 'store'])->middleware('perm:product-service.create');
                     Route::post('import', [ProductController::class, 'import'])->middleware('perm:product-service.create');
+                    
+                    // OS list for product configuration - must be before {id} routes
+                    Route::get('os', [ProductController::class, 'getOsList'])->middleware('perm:product-service.view');
+                    
                     Route::get('{id}', [ProductController::class, 'show'])->middleware('perm:product-service.view');
                     Route::get('{id}/os', [ProductController::class, 'getOs'])->middleware('perm:product-service.view');
+                    Route::get('{id}/operating-systems', [ProductController::class, 'getOperatingSystems'])->middleware('perm:product-service.view');
                     Route::put('{id}', [ProductController::class, 'update'])->middleware('perm:product-service.edit');
                     Route::delete('{id}', [ProductController::class, 'destroy'])->middleware('perm:product-service.destroy');
                     Route::post('{id}/duplicate', [ProductController::class, 'duplicate'])->middleware('perm:product-service.create');
@@ -115,6 +122,7 @@ Route::prefix('v1')
                 Route::prefix('orders')->group(function () {
                     Route::get('/', [OrderController::class, 'index'])->middleware('perm:order.view');
                     Route::get('/datatable', [OrderController::class, 'datatable'])->middleware('perm:order.view');
+                    Route::post('/upload-proof', [OrderController::class, 'uploadProof'])->middleware('perm:order.create');
                     Route::post('/', [OrderController::class, 'store'])->middleware('perm:order.create');
                     Route::get('{id}', [OrderController::class, 'show'])->middleware('perm:order.view');
                     Route::put('{id}', [OrderController::class, 'update'])->middleware('perm:order.edit');
@@ -143,6 +151,7 @@ Route::prefix('v1')
 
                 // Payments (module: payment)
                 Route::prefix('payments')->group(function () {
+                    Route::get('for-select', [PaymentController::class, 'forSelect']);
                     Route::get('/', [PaymentController::class, 'index'])->middleware('perm:payment.view');
                     Route::post('/', [PaymentController::class, 'store'])->middleware('perm:payment.create');
                     Route::get('{id}', [PaymentController::class, 'show'])->middleware('perm:payment.view');
@@ -150,6 +159,27 @@ Route::prefix('v1')
                     Route::delete('{id}', [PaymentController::class, 'destroy'])->middleware('perm:payment.destroy');
                 });
 
+                // OS Groups & OS Entries (module: module-vcenter)
+                Route::prefix('os-groups')
+                    ->controller(OsGroupController::class)
+                    ->as('os-groups.')
+                    ->group(function () {
+                        Route::get('/', 'index')->middleware('perm:module-vcenter.manager')->name('index');
+                        Route::post('/', 'store')->middleware('perm:module-vcenter.manager')->name('store');
+                        Route::get('{id}', 'show')->middleware('perm:module-vcenter.manager')->name('show');
+                        Route::put('{id}', 'update')->middleware('perm:module-vcenter.manager')->name('update');
+                        Route::delete('{id}', 'destroy')->middleware('perm:module-vcenter.manager')->name('destroy');
+                    });
+
+                Route::prefix('os')
+                    ->controller(OsController::class)
+                    ->as('os.')
+                    ->group(function () {
+                        Route::post('/', 'store')->middleware('perm:module-vcenter.manager')->name('store');
+                        Route::put('{id}', 'update')->middleware('perm:module-vcenter.manager')->name('update');
+                        Route::delete('{id}', 'destroy')->middleware('perm:module-vcenter.manager')->name('destroy');
+                    });
+
                 // VPS (module: module-vcenter)
                 Route::prefix('vps')->group(function () {
                     Route::get('/', [VPSController::class, 'index'])->middleware('perm:module-vcenter.view');
diff --git a/storage/app/public/payment-proofs/48lYy8R6JFgbqasJy5dfSLxWR1miOvpUIjejIPle.jpg b/storage/app/public/payment-proofs/48lYy8R6JFgbqasJy5dfSLxWR1miOvpUIjejIPle.jpg
new file mode 100644
index 0000000..8322426
Binary files /dev/null and b/storage/app/public/payment-proofs/48lYy8R6JFgbqasJy5dfSLxWR1miOvpUIjejIPle.jpg differ