Flipkart - Promised cashback not given

I purchased a mobile phone from Flipkart on ** Nov ** during the sale. I made the purchase using Flipkart Axis Bank Credit Card. I was assured *% cashback of the purchase value while buying the product (Rs. ***). The cashback was supposed to be credited during the Nov billing cycle. On checking the Nov’** credit card bill I observed that only *.*% (Rs. ***)cashback has been processed.
On contacting Flipkart they accepted that I am eligible for *% cashback but did nothing to resolve the issue. Reference Incident: OD****************** [Incident: IN*******************]
On contacting Axis bank they denied processing additional cashback stating that the transaction was done on Phonepe App which is incorrect. I provided them with the receipt proving that the product was bought on Flipkart and not on Phonepe however there was no response and they closed my service request without resolving the issue. The service request I raised are ********, ********.
Probably, it was issue with the merchant code provided in the transaction by the Flipkart. Flipkart customer support has been pathetic with executive misleading me promises and wrong reasons for the issue.