Flipkart - Serial Number Mismatch between Invoice and Product

I have ordered Apple Macbook Air core i* *th generation laptop from flipkart, it was delivered on **th July, ****. Upon unboxing and starting the laptop I observed the Laptop serial number and the invoice serial number mismatched! I raised a complaint on */**/**** In Flipkart Customer Support, they failed to provide me any solution till **th July. On **th July the schedule a pick up for returnIng the product and refund of the amount. The scheduled the pick up on **th July. Suddenly on **th July without any prior appointment one Delivery guy came to pick up the product , as it was not the scheduled date, i was not present. The pick up guy rescheduled the pick up for **th July, though stating in the app that Pick up could not be completed because of different product. After that Flipkart cancelled the return and refund request. And upon contacting them they told me they can not raise a refund issue any further. Now in this scenario what I have to do? I have spent ****** rupees for the laptop whose serial number is wrong. I can not claim warranty , i am denied any replacement or refund from Flipkart.