Amazon India — Not received cashback

Address:	560047
Website:	amazon.in

I ordered a mobile from amazon.in site on 3rd march 2016. where there was an offer for 10 % cashback for SBI card holders. After the order I got mail that Im eligible for the offer and will receive the cash back amount by 1st June 2016.
But not yet received. I mailed them about this, they asked my bank statement, then they told me that Im eligible for the offer and will get the amount in 2-3 days, in case of not receive any amount again inform them. So now its July, I again mailed them, now they are saying that Im not eligible for that offere as I paid by sbi internet banking, which is completely wrong. I paid by sbi debit card.
Attached the image of there response mail after the payment
So I need help, Looking for your positive response