HDFC Bank — Iphone Cashback Not Received in HDFC Bank Account

Dear Team,
I had purchased an iphone 11 on 11-Feb-2020 and i am eligible for 6000 rupees cashback as i have purchased my iphone through HDFC debit card it was clearly written on credit Card slip about the cashback.
And, this cash back was supposed to get credited within 120 days from the transaction month and this time period has already crossed and still didnt get any amount.
so, requesting you kindly look into matter and suggest whom to contact for the same.

Regards
Pratul Goel