Coolwinks — Received a wrong product but they are refusing to refund my money

I received the wrong product from coolwinks and complained about this to coolwinks. They placed a return request and I returned the same product which I received because it was different and also of too poor quality that it was not even worth rupees 100 but they charged me Rs.1700 for that. But even after reaching the product to their warehouse, they didn't even start the process of quality check for 3 days. After complaining to the customer support they started the quality check and after 1 day they sent an email to my registered email that they have received a non-coolwinks product so they can't refund my money. They even sent an image too which was completely different from the eyeglass which I returned. Now they are putting all the blame on me that I have sent the wrong product and that's why they can't refund my money. Why didn't do the quality check when they took the product from me during the return and now they are saying that they can't refund because they have received a different product.