Amazon.in — Not receiving cash back

Address:	New Delhi, Delhi, 110048
Website:	amazon.in

I have ordered mobiles phones from amazon site in the month of May 2015. I have not received my cash back from amazon company till Oct 2015. I am taking many followups. But it is not getting resolved by Amazon. They told that company will give cash back after 90 days. Amazon executives are just guiding me to contact with my bank. but they are not able to resolve my problem completely. 6 months is a long period to waiting for benefit as a customer. I am very disappointed with Amazon service.