Reserve Bank Of India [RBI] — Not refunding my money in my account

I purchased a product of Rs 6999 from Amazon on 16th July 2016 using Indian Overseas Bank's debit card. But same day I cancelled the order and Amazon refunded the money next day. But even after 4 weeks, bank has not credited money in my account. I had complained about this on 31st July and the complaint no is MI 290709.
Refund reference no from Amazon is 81365274332746199619876391855.