Faulty goods, faulty store

I bought a battery for my Samsung S21 at Chatz Cellular Greenstone . I may as well have kept my old one. This battery goes from 100% to 77 % in 10 minutes. I went back there to exchange it, only to find the shop is all closed up. Looks like they have closed down. Everything papered up. I should have known something was up when the gentleman behind the counter started explaining to me the does and don't of battery usage. Batteries aren't cheap and paying for something that doesn't do what it's supposed to especially in this economic climate is annoying as well as frustrating. Where did honesty go and selling good quality goods.