Flipkart — rejected the delivery imei mismatch, but not even an option available to provide an imei number at the time of purchase

I have ordered a pixel 6a at flipkart with exchange of my old phone. At the time of purchase it did not ask me to provide a IMEI number. At the time of delivery my product was valid from their verification app yaatra. But IMEI does not match with the delivery person application. It shows like IMEI did not match. The thing flipkart did not even ask the Old phone IMEI number in the first place. I have cancelled and reordered, the same issue keep happening with flipkart