Kotak Mahindra Bank — Cashback not received

Purchased iPhone 13 on March 20 2022 using my Kotak Bank Debit Card. There was an offer NoEMIOnlyCashbck that when used Kotak bank debit card i will be receiving cashback of 6000 within 120 days of the transaction. Its been more than 120 days and cashback is not received yet. Called kotak bank the customer support was rude and asked me to contact merchant.

I contacted merchant who is pi international and they told me that cashback is banks responsibility. I am attaching my receipt of payment and in that it is clearly mentioned

"You are entitled for a cashback of Rs. 6000 on card. It will be posted in Customer account n 120 days from the last date of the action month on a best effort basis to all and active card members accounts only"