Amazon India — Non fulfillment of promotional offers

Address:	560003
Website:	amazon.in

I had placed an order on amazon.in for a foot massager jsbhf68 compact portable foot massagerwith heat (Red) sold by jsb healthcare vide order no[protected] on 25th october2016. The product was delivered on 29th oct 2016. The payment of rs 5999 was made using a sbi debit card, which qualified for a cash back of 15% as per the promotions offered by amazon.in at that time. The payment made by the debit card has also been debited to the savings bank account with sbi on the same date. Inspite of numerous phone calls and followup e mails, i have not been able to get the cash back till date (Which is about 4 months).
I believe amazon.in is not very serious about the fulfillment of offers and these offers are not genuine. If they cannnot fulfill the offers for small values, how can anyone hv confidence for placing orders of higher values.
Hall be thankful for getting this issue resolved