diff --git a/app/Nova/Actions/CheckOnlinePayment.php b/app/Nova/Actions/CheckOnlinePayment.php
index d201feb..6c83b91 100644
--- a/app/Nova/Actions/CheckOnlinePayment.php
+++ b/app/Nova/Actions/CheckOnlinePayment.php
@@ -10,7 +10,6 @@ use Illuminate\Support\Facades\Http;
 use Laravel\Nova\Actions\Action;
 use Laravel\Nova\Actions\ActionResponse;
 use Laravel\Nova\Fields\ActionFields;
-use Laravel\Nova\Fields\Code;
 use Laravel\Nova\Http\Requests\NovaRequest;
 
 class CheckOnlinePayment extends Action
@@ -89,7 +88,7 @@ class CheckOnlinePayment extends Action
 
         $keyValueListHTML = '';
         $response->collect()->each(function ($item, $key) use (&$keyValueListHTML) {
-            $keyValueListHTML += "<li><span>{$key}:</span> <strong>{$item}</strong></li>";
+            $keyValueListHTML .= "<li><span>{$key}:</span> <strong>{$item}</strong></li>";
         });
 
         return Blade::render(<<<HTML