No customer service.

I have been calling Mtn Direct for more than a month now for assistance. I upgraded to an Iphone 8 on the 25th of November via the call centre, they delivered my iphone to me on the 25th. On the 2nd of December, exactly a week after I received my phone it started getting hot, rebooting and I can’t use it since. I went to 2 MTN shops for help, emailed MTN more than 6 times and called the call centre- i dont even know how many times (more than 10 times) but still I have not been granted a new phone or helped at all. All feedback i receive is that the supervisor will contact me but it still hasn’t happened after 5 times that I’ve been promised that. I am fed up with the horrible customer service and am honestly desperate to receive my new phone because I feel that it is unfair for me to pay my bills each month (which I understand is also for the data) but you also pay for the phone which I can’t use. I still have the phone in my posession because the 2 MTN shops I went to does not want to take the phone because I orederd it via the call centre and they said the phone should be collected from my home via the people who delivered it to me in the first place. I honestly don’t know what to do anymore!