EXTREMELY FRUSTRATED

I have upgraded my cell phone contract with Autopage in August 2015. Since then I have been experiencing endless problems with my Sony Experia. Once you charge the phone it gets over heated and then shuts down completely. I went back to Autopage within the month that I took the phone and they sent the phone for repairs. They said the battery was changed and soft ware upgraded, however the problem persisted. In Jan 2016, the phone shut down completely with the same story, it overheated and then shut down completely. I tried charging it but it does not want to come on. I took it back to Autopage and they refuse to replace my phone, saying it needs to go back 3/4 times for repairs before a handset is replaced. I find this totally outrageous. They also advised that they cannot send it for fixing as they are closing down and I should wait for the 1 March to take it to Vodacom to have them attend to it. I took it to Vodacom and they say that they cant repair/replace as the contracts have not been finalised. I am without a phone since Jan 16 and am using my sim card in other phones to get by. We pay our accounts religiously and get no service in return. Pathetic service.