add

server/app/Http/Controllers/Api/V1/InteractionController.php

@@ -462,7 +462,7 @@ class InteractionController extends Controller
         if (empty($interaction)) return $this->error(ErrorCode::INTERACTION_NOT_EXIST);
         $black_list = '';
         $black_list .= $user_id.',';
-        $interaction->black_list =$black_list;
+        $interaction->black_list =$interaction->black_list . $black_list;
         $ok = $interaction->save();
         if ($ok) return $this->api('');
         return $this->error(ErrorCode::OPERATION_FAILED);