Amazon India — wrong product sent and no refund given after promising and o response

Address:	600039
Website:	www.amazon.in

I purchased a detek weighing machine from amazon on aug 29, 2017 for rs.725 and paid cash on delivery. After opening i found it was a wrond non branded product was sent. I returned and was replaced with same non branded product again. Second time they gave me a returnless refund when i asked to take the product and refund my money. This happened on sep 10, 2017. I am following them since then but still my money is not refunded. They asked me to check my bank and i also did that and sent mail response from my bank also. Still no reply or no action.
I am really frustrated by following them and sending mails.

I need my money immediately. I can provide all email conversation even with my bank.