Morestore — Unethical Behavior

I had purchased a bag of raw rice from More Store, RA Puram, Chennai 600028 early May 2021 via Amazon-More delivery service. A few weeks later when I opened the rice bag it had a rotten rat with several insects due to the dead rat in it. I returned the bag to the same store. After a lot of fuss over the fact that I bought thru Amazon and that they cant directly take it back etc they took it back. The manager promised to send a replacement bag. It has been more than a month since I returned I have neither got the rice bag nor the refund money. They don't pickup the call and if they do they dont give any proper answer. Firstly, it is very unethical to sell sub-standard products and secondly not acknowledging and correcting the issue immediately. Please help!