diff --git a/partner-masterpulsa-voucher.js b/partner-masterpulsa-voucher.js
index b81b306..3cb80dd 100644
--- a/partner-masterpulsa-voucher.js
+++ b/partner-masterpulsa-voucher.js
@@ -115,7 +115,7 @@ function parsePaymentResponse(message) {
 function rehashRefnum(refnum) {
     var hashed = refnum;
     try {
-        hashed = hashed.replace(/A/g, '1').replace(/B/g, '2').replace(/C/g, '3').replace(/D/g, '4').replace(/E/g, '5').replace('/F/g', '6');
+        hashed = hashed.replace(/A/g, '1').replace(/B/g, '2').replace(/C/g, '3').replace(/D/g, '4').replace(/E/g, '5').replace(/F/g, '6');
         hashed = hashed.substring(0, 15);
     }
     catch(err) {