Mtn
Mtn service provider poor service

Hi
i bought a phone on contract (Lumia 920) from MTN service provider, after a month the phone stopped working, i took it back to the store for warranty check up, after two weeks the brought it back and said there was nothing wrong with it. after three weeks it stopped working again, i took it back to the store for check up. i waited three weeks and after that they brought it back and told me that there is nothing wrong with the phone.i am not willing to take that old phone i have been without that phone more than i have it but im still paying full amount. mtn is being difficult they do not even give you a phone to use while yours is on the assessment please help i am not willing to take that phone back.