HDFC Bank — cashback when purchased mobile through amazon

Address:

Dwarikapuri, Mathura, Uttar Pradesh, 281004

I purchased mobile on amazon under 5% hdfc debit card cashback scheme on 13th august but still after more than 90 days no cashback is received.
My registered mobile number is [protected].
After that i also do many payments through debit card on different merchants under 5% and 10% scheme.

I think no such cashback received... Please solve my problem as soon as possible