I need a replacement for my phone from IPhone Drip!

My experience with these people have been the worst, they don’t even deserve this one star rating. It’s either they give me a replacement or my money back coz they sold me a phone that was half dead. When I bought the phone it was not working at all it didn’t want to charge, they got another phone which was making funny sounds when you make a video or receive calls. Finally I got another phone which was not my desired color but I took it coz I didn’t have a choice, the phone worked for a less than 2 months then I couldn’t receive calls anymore, I couldn’t take videos or listen to music. Took the phone back they fixed it and it worked for atleast 4 weeks, battery started swelling up, gave my fiancé to take it back they charged him R400 for battery replacement yet he claims that when they opened the phone it was rusty inside and they had to use certain sprays to loosen the battery. After few weeks of using it again it stopped working totally. They kept taking the phone and fixing it yet they didn’t want to refund me or get me a replacement. I’m back to square one with a phone that cannot take calls, can’t record voice notes, I can’t take videos and the phone overheats every minute. The owner promised to replace it, I’ve been waiting for long and when I text him he’s very rude towards me.