Cellphone nightmare

I have never been so disappointed in the service im getting from MTN. I was offered an MTN cellphone contract over the phone which I accepted not only because I needed a new phone but also because I've previously dealt with MTN and had a great experience. The handset (Samsung J5 Pro) was delivered, I got a screen protector and a cover for it. The nightmare started about two weeks later when the phone froze, I couldn't do anything answer calls, type or even switch it off. I then let it's battery die hoping it would reset once I switch it on but that didn't happen. So I took it to the MTN in Eyethu Mall but they said I had to take it to an MTN Direct Store. I went to Centurion because it's closer to my workplace but the lady who assisted me said she couldn't take the phone because the only thing I didn't have with me was the pin used to open the SIM card holder. When I finally found it I went to the store in Carlton Centre as it was convenient at the time and didn't want to go through what I went through at Centurion. Little did I know that the phone was being taken in for repairs instead of having it replaced like I had expected and told by the lady at Centurion. I then receive a text informing me of aR2700 odd repair cost, I rep**** with NO because I felt it was unfair that I had to pay that much for a clear factory fault in my eyes especially a phone that was two weeks old. So now I'm stuck with a phone that doesn't work yet my account is being debited. I've had to purchase another handset in the interim. It seems to me that the handset was faulty even before it got to me and now I've been ******* into funding its repair costs.