Amazon India — refund amount not yet received

Address:

Chennai, Tamil Nadu, 600097

I have ordered a laptop battery worth rs.1953 on july, 03 from amazon india (www.amazon.in). after receiving the product it worked for 3 days then it stopped working so i returned that product on july, 15 and asked for refund. They asked to do self return and they will pay back the courier charges so i paid extra 500 rupees for courier. The refund got failed and they are saying that they have reinitiated the refund. But it has been more than 4 months, they are giving the same response. I am fed with their executives and it's like mental torture. So please take necessary action.