HDFC Bank — Cashback not received.

Address: Bhim Garh Kheri

I had purchased an iphone 11 from gurgaon on 20/1/20. The phone was on an offer from the hdfc bank which said 10% of the total amount that is 6000/- would be credited in the account within 4 months of the purchase. It has been over 4 months now and the cashback hasn’t been credited yet.
I purchased the phone from galleria market, gurgaon.
Please look into this issue and take the necessary steps possible. The email mentioned is registered with the account the phone was purchased with.