Unhappy Service from Apple and MTN

Good day Apple

As an Apple customer I am really disappointed with the out come off the below.

I purchased an I Phone 8 from Mtn in October 2017.

In November the phone started glitching, I was going to have the device taken in and couldn't make it during the week, within the week prior to me taking the phone back to Mtn the phone started heating up and felt this on the home screen button, as the norm I left the phone to cool down, later when I returned to the phone I couldn't unlock the phone and some error massage came on stating something about the touch unlock, on examination of the phone I noticed that the home screen had shattered, I have never dropped the phone nor mishandled the device and concluded that due to the home button and phone heating up it caused it to shatter. I turned the phone off and left it off for 10 minutes, after 10 minutes I tried switching on the phone and it refused to pass the Apple logo screen and switched off it self and back on till the battery died and never turned on. I had the phone booked in at Mtn for assessment on the 6 December 2017. Mtn reverted stating that there was no faults picked up on the phone and no signs off over heating I expanded the above to Mtn and was told I need to call Apple myself inorder to get a letter stating that the phone has issues, I called Apple Europe and explained my situation and was told that this is wrong of Mtn to make me call to do there work, Mtn came back stating I need to pay +/- R5500 in order to get the phone fixed as it's out of warranty (1 month old phone out of warranty?) I told Mtn to escalate this with Apple as I am totally unhappy with this service being received, Mtn says Apples refuses to fix the phone as the home screen is broken and voids warranty, as a customer this only occurred due to a faulty device which was purchased, if this is the service from Mtn and Apple I highly recommend customer to choose anther service provider and a competitor rather then Apple, it's now the 16 January 2018 and my phone is still with MTN. Please can I be explained why is this not being resolved after all I have been an Apple user for over 4 years and sad to see it come to this due to a Faulty device which I have to suffer as no one is willing to admit that this is not a fault of the customer but off the device. If no faults has been detected please advise why did the phone glitch? Why did the phone heat up? Why did the home screen shatter? Why did the phone not switch on? I have all those questions which is still unanswered till date. 1 month and 10 days and still waiting.