I pay for a phone that does not work

I was out of the country for 2 weeks & did not contact MTN to roam, instead put my phone on airplane mode & used wi-fi. When I returned this week I was not able to access some apps on my phone. I called MTN Tuesday (29 Sept) & they explained that since my airplane mode was on they opted to switch off my GPRS (and still asked me if I had asked someone to turn off my GPRS, obviously I had not). Fist time I contacted MTN I was put on a conference call with the 808 &Tech dept. they shouted back & forth & nothing was resolved. I called again later that evening & was told would be fixed 2- 24 hours. It is now Friday (2 Oct) over 5 people later, this problem has not bee sorted. Instead my phone now looses signal & does not work outside of Johannesburg & cannot make calls. Although the tech team said they fixed it, it still reflects on 808 & my side that it has not been resolved. I am tired of calling them (them claiming they contacted me when they haven't)& tired of being told to switch my phone off & on. I want this problem fixed & not respond saying to tried to contact me (which I never get) Everyone at the call centre was respectful but MTN PHONE still useless to me.