diff --git a/gentong.js b/gentong.js
index 6454a32..87420d5 100644
--- a/gentong.js
+++ b/gentong.js
@@ -100,9 +100,9 @@ function topupRequest(task) {
                 responseMessage =  result.direct_ack.info[0];
 
                 if (result.direct_ack.request_status[0] == 'OK') {
-                    responseCode = 68;
+                    responseCode = '68';
                 } else {
-                    responseCode = 40;
+                    responseCode = '40';
 
                     var new_response_code = responseCodeFromMessage(responseMessage);
                     if (new_response_code) {