Another bad experience with MTN

Hi. So April 2017 I took out a contract with MTN. There was an issue on their side and was only able to use my phone a month later. A few months later at the beginning of November the phone starting going faulty. So it was booked in for repairs on the 16th November 2017. For two weeks I kept calling the Cavendish Square branch and no one answers ever. Eventually I got through and they said my phone can be collected. I got there and my phone was not repaired neither could they tell me what the issue was. At that point I was really upset and left with my phone. A few days later they called apologizing and telling me it was their fault for not sending proof of purchase to the repair centre. So I took they phone back. I kept calling leaving emails and no response about my phone. A week ago a staff member left a message apologizing saying the phone is still with Huawei and that's it. I don't know whats wrong with the phone or what the issue is. It is now the 8th February 2018 and I still don't know. I'm tired of going into the store because I end up just getting more upset. What upsets me more is the problem lays with MTN and Huawei for giving me a faulty phone. This is really unacceptable and I'm really fed up with MTN.