HDFC Bank — hdfc bank iphone 11 cashback not received

I have bought my iphone11 with hdfc bank credit card on 29/feb/2020 from unicorn store, defence colony, delhi. As mentioned by hdfc bank (To receive a cashback within 120 days from the transaction day and time) but i haven’t received my cashback till now, it is more than 120 days. I have tried to connect hdfc customer care but unable to connect to them. Also, i have tried to contact the showroom from where i have bought the iphone so they said to check with your bank. Hope this issue gets resolved and cashback will be credited as soon as possible.