Poor customer service,angry at MTN and Xioami

Good Day I have a problem with my xiaomi mi-4 that is under contract with MTN until August 2018. I took the phone last year to MTN(N1 City) for repairs as the heats up,shuts down and restarts as well as the sound stopped working. I received the phone after about 5 weeks and it worked fine even though it had a different IMEI no. A couple of months later it started doing the exact same but this time it looked like the screen is busy melting as it starting showing a rainbow colour in the top right hand corner of the screen. In February 2018 I took it to MTN(Vangate Mall) for repairs and about a month later the phone came back from repairs again with a different IMEI no but this time the phone was not repaired as it came with the back cover of the phone damaged. The consultant(SIYA) at MTN (Vangate Mall) was made aware of it and he booked the phone again in for repairs. I went back in March to get the phone back and immediately when the consultant(SIYA) opened the box the phone was still in the same condition and not repaired. It has been an ongoing saga between me and MTN(Vangate Mall) regarding my phone which has now let to the manager telling me that there is nothing she can do as the Manufacturer(XIAOMI) has told them that they will not replace the phone as it has different IMEI no and that it is already out of warranty which would mean that they can fix it but I need to pay for repairs. I told the manager at MTN(Vangate Mall) that I cannot be paying for repairs as the phone is still under contract as to which she agreed but yet she lets them tell her this nonsense. On 21/3/18 the manager called me and said that the Manufacturer(XIAOMI) said that they will not replace the phone as there are not exchange form supp**** when it was booked in for repairs. I told the manager I never received an exchange form from MTN(N1 CITY) when I got it back from repairs and her answer to me is that she called MTN(N1 CITY) and they said that the form is already archived it is not her problem and that I need to speak to them about the form. I do not know what to do as MTN has not resolved the problem and me as the customer need to do their work. This is totally unfair and I want a new phone. MTN is unreliable and how now respect for me as a customer and they do not deliver any customer services.

I only received a new Xioami Mi-4 on 23/07/2018 but they not even give my an option to choose a different phone of the same value.The same day when i got home this brand new phone started heating up again and i had to stop using it to let it cool down which will result in me having to go through the same process again.Mtn and Xioami have absolutely no customer service and if i was not not persistent in emailing Xioami almost every single day i still would not have received a new phone. Both companies know this phone is a problem but instead of doing the right thing and give me a different phone they give me the same phone.I thought at the time of taking out the contract that seeing that everyone is using Samsung,LG,Huwaei i would like to go for something different but from now i will stick to the fami**** and now i know why people don`t like change as sometimes change is no good.

I am absolutely appalled at how they operate and yet they work in an customer service industry. I would like to make people aware of this problem and remind them the nonsense of your customer rights means absolutely nothing to them. If you come into the MTN(Vangate Mall) store you will wait until your grey for assistance and the have a machine in front where you have to take a ticket but that thing does not work.