HDFC Bank — cashback of 6000 rs on iphone 11 not received

I bought iphone 11 on 28th december 2019 and as promised i have not received any cashback till now which obviously more than the given timeline i called previously too the banker said it will definitely be received prior 31st march i waited till 27th april then i mailed you in email address stated on site which is [protected]@hdfcbank.com which stated that due to ongoing covid 19 situation they will take longer to respond it’s now been 18days more than the given timeline again. Kindly explain when i will receive the amount or else don’t make fake offers like because right due to covid 19 situation you r are not taking calls as well for complaints.