diff --git a/app/Http/Controllers/iLinkTransactionController.php b/app/Http/Controllers/iLinkTransactionController.php
index 1a61a56..b6d66da 100755
--- a/app/Http/Controllers/iLinkTransactionController.php
+++ b/app/Http/Controllers/iLinkTransactionController.php
@@ -232,8 +232,18 @@ class iLinkTransactionController extends Controller
 
 
         $data = $request->all();
-        if (isset($request->cvv) && !is_numeric($request->cvv))
+        if (isset($request->cvv) && !is_numeric($request->cvv)){
             return $this->errorResponse('errors.invalid_cvv');
+        }
+
+        // Verify transaction id
+        $transaction_id = $request->input('payment_transaction_id');
+        if (!empty($transaction_id)) {
+            if ( WalletIlinkTransaction::where('payment_transaction_id', $transaction_id)->exists()) {
+                return $this->errorResponse(trans('errors.payment_invalid'), 400);
+            }
+        }
+
 
         $transaction->fill($data);
 
diff --git a/resources/lang/en/errors.php b/resources/lang/en/errors.php
index 01f21eb..f757b9a 100755
--- a/resources/lang/en/errors.php
+++ b/resources/lang/en/errors.php
@@ -88,5 +88,6 @@ Paying network : :network :country',
     "amount_not_allowed" => "This amount is not allowed. It must be between :min and :max",
     "transaction_already_completed" => "This transaction has already been completed",
     'paying_network_api_failed' => "Request to API paying network failed",
-    'transaction_not_supported' => "This transaction is not supported"
+    'transaction_not_supported' => "This transaction is not supported",
+    'payment_invalid' => "Invalid payment"
 ];
diff --git a/resources/lang/fr/errors.php b/resources/lang/fr/errors.php
index b136cd3..c1bb592 100755
--- a/resources/lang/fr/errors.php
+++ b/resources/lang/fr/errors.php
@@ -88,5 +88,6 @@ Réseau payeur : :network :country',
     "amount_not_allowed" => "Ce montant n'est pas autorisé. Il doit être compris entre :min et :max",
     "transaction_already_completed" => "Cette transaction a déjà été éffectuée",
     'paying_network_api_failed' => "La requête vers l'API du réseau payeur a échouée",
-    'transaction_not_supported' => "Cette transaction n'est pas supportée"
+    'transaction_not_supported' => "Cette transaction n'est pas supportée",
+    'payment_invalid' => "Paiement invalide"
 ];