Flipkart — Replacement not done and cancelled it

I purchased SanDisk Ultra 128 MicroSDXC Class 10 120 Mbps Memory Card
Seller: CorrectDealsOnly
My order I'd - OD[protected]
Of Rs 920 on 9 march 2022. It was delivered to me on 15 march 2022. I found it was not working in my phone or it was faulty so wanted to return it or replace it. I asked for replacement on 19 March 2022 . As my refund and replacement last date was 21 March 2022, my refund request was within this. They started replacement request but before the product gets replaced they cancelled it after 3 days on its own don't know why. And after that they are saying your product can't be refunded or replaced as time gets over. What's my fault I requested the replacement before the last date. You cancelled it on your own and cheating me . I want my product replaced or refunded as soon as possible.