HDFC Bank — cash back on iphone 11 not received

Hey, i purchased an iphone 11 on
16th january 2020 from imagine stores, elante mall chandigarh. The said purchase was made with my hdfc credit card with the scheme offered by the bank of instant payback of ₹6000 on this sophisticated gadget within 120 days but unfortunately i have not received the promised cashback yet and due to the shortage of staff because of covid19 i have not been able to reach hdfc bank’s customer service.
Consequently, i’m posting it here it will be 6 months on 16th of june, anticipating the issue to be resolved as soon as possible.