Incorrect repairs / NO HELP THEREAFTER

I booked my phone in at MTN Menlyn on 10 Jan 2018. REF ********** ********** The phone was still working, but the system had slowed down and would randomly switch on and off -thus like a software problem. I brought in the phone as I do have a spare and was told it would take 8-10 working days. When the phone was booked in there was a small crack on the bottom right hand corner, it was noted. When I was signing the documents, I specifically asked the consultant Kabelo Mohlale about the clause about the payment. We came to the agreement that amount wont be payable as the phone was still working. The phone had fallen a few days previously, but there was no use in bring in the phone as I was told the repair centre would only open on 8 Jan. The fact that the screen was cracked, was not the reason for the repair as the phone was working. Three weeks later (not 8 to 10 working days) after being shunted around between MTN Menlyn and the repairs centre as I did not have my ref number. I phoned to find out what was going on. I was told I have to pay just over R1000 to have the phone repaired, because the screen was cracked. I tried to explain many times that the phone had worked after the crack so that would not be the reason for the repair. I must add the the consultant at the repair centre did not really want to hear my explanation. I asked to speak to the manager but was told he was busy, I held on, but still he was busy. I left a message if he could please contact me. No one bothered to call back, two days later my husband receives an sms about the repairs. I do not know why this was not sent to me. I have tried to get hold of the manager at the repair centre to resolve the matter. I get no feedback I made a complaint on the MTN website - no feedback I have 3 contracts with MTN and quite frankly will cancel them soon, if a simple decent explanation cannot be given or a clients complaint even considered