HDFC Bank — 6000 cashback not received for buying iphone 11

Address: Sahibabad, Ghaziabad

I have bought my iphone11 with hdfc bank debit card on 29th september 2019 from reliance digital. It was mentioned by hdfc bank (To receive cashback of 6000 within 120 days from the transactional month end) i haven’t received my cashback till now, it is more than 120 days. I tried to contact bank they asked me to wait a little longer and i have also asked at reliance digital they asked me to contact with bank. It has been more than 6 months now and i havent received any cashback.