Broken phones

I upgraded my contact in February and was given an iPhone 5S. 5 months later, the phone just stopped working and I took it to MTN Clearwater where I got it from. They booked it in and 3 weeks later I was given a replacement phone. Apparently it was a new phone but was not in a box and had already been set up. When I got home and wanted to use the phone, I discovered that the phone was faulty as it would not go past the Apple startup logo and it kept going off and on. I took the phone back within a few days and it was booked in once again. 3 weeks later I get an SMS stating that I owe a service fee of R330 because apparently \find my iPhone"was not disabled and they have not be able to repair the phone. 3 WEEKS LATER! This phone is not even listed under my devices because I was never able to use this phone in the first place. This is most likely someone else's broken phone that was passed onto me. Mtn better sort this out else they must cancel my contract and I'm not paying and termination fee. """