HDFC Bank — iphone 11 cashback offer

I bought iphone 11 from ivenus store (Inorbit mall, vadodara) on 18 march 2020 through my hdfc credit card. As hdfc bank and their customer care promised i should get cashback of 6000₹ within 120 days. However, i haven't get cashback till today. I have also complaint via email but they don't even think their duty to revert back on this. I hope after complaining here, i will get my cashback soon.

I requesting hdfc bank to resolve this issue soon.

Thank you.