Amazon India — not got the refund in the account

Address:	Agra, Uttar Pradesh
Website:	www.amazon.in

I bought a product from amazon in october, and for which they delivered me a wrong product so i request them to get in return and in exchange they assure me that i will get the refund amount in my account within 7 days but i had still not got any kind of help. I even contact the customer care 15-20 days back and where they assure me to help me in getting my amount refund but still no one has help me and still i have not got my refund amount.
It is also showing that they have refunded the amount but the bank is also unaware about this and amazon is also not providing any kind of help. I request you to kindly help me to get my amount back.