HDFC Bank — I haven't received refund for a payment made to amazon via hdfc account

Address: Hyderabad

I have ordered and item and cancelled it before arriving.i have made the payment using my hdfc bank account.its been 15 days but i didn't recieve the refund.i contacted amazon they sent me a reference number indicating the issue of refund.but bank has not sent me refund till now.i am not able to contact hdfc.it is very difficult to contact hdfc to solve issues.