Cannot use my phone but still have to pay, no help from Vodacom

My third time renewing my contract with a Nokia Lumia phone, never had a problem before but this phone I got this time had troubles from the start. Google revealed that all 3 problems were common with the phone. Vodacom said its because Nokia and Microsoft does not support the phone since July this year. The problems went from sometimes to daily switching off, loosing network and camera not working. I have been querying for months and kept getting told my email will be responded to. When I phoned, they said I should hand the phone in. The phone now has a hairline crack and they says it must be fixed first at nearly R2000 before they can fix the other problems. I have given evidence of the emails, an affidavit that I never dropped the phone and that the phone has those problems and it cannot be fixed. I do not want a fixed phone because it will have the same problems. I am unhappy to pay for a phone that does not work properly and the hairline crack being fixed will not fix the problems with the phone. I asked for written confirmation of their response so that I can refer it to the NCC , now my request for written confirmation has been escalated???? They do not even want to put in writing what they are saying. When I said I need the written feedback to lodge my query at the NCC, the guy said he has many of those cases, do not care?