Utterly poor service from MTN

I took out a contract with MTN for the new Hisense H60 in May last year. 3 months into the contract the screen started overheating and was glitching. I took the phone back to MTN. There is no phone in the store to call and follow up. I spoke to one of the ladies who sent the phone to MTN. she tells me that MTN says there were scratches on the camera lense and there is nothing wrong with the phone. They sent the phone back 2 months later saying the phone could not be replaced. When i get the phone back the screen starts overheating and glitching again. This time it got even worse. I went back to Beacon Bay branch and the guy that assisted me could see the phone glitching to the point that we could not see anything. MTN again said there was nothing technicians said there was nothing wrong. i got the phone back again. I then spoke to the regional manager of hisense who said to me i should send him a video of what was happening. He advised me to take the phone back to the store and for the last 2 weeks i have gotten no response to my complaint. No one in the store is assisting me. I have reversed my debit order until such time my phone has been sorted dare i be listed for a missed payment The service of MTN is shocking. They don't care as long as they get their money. To hell with the customer. This is the worsed service i have every had and regret taking any contracts with MTN.