HDFC Bank — I phone cashback not received

Hi I have purchased an i phone 11 in january but till date my cashback is not credited . Which was to be credited within 120 days .I have been trying to call the customer care but its shutdown from last 3 months now and nowhere to reach for this complaint.

I have already mailed the support id but its been over a month no response is been given.
Kindly let me when will I receive it.

Thanks
Hardik Sabharwal