Why vodacom why

Im really having a hard time with vodacom this year. I got a phone on contract last year march, the phone started to reset itself switching of randomly and now stopped charging, took it into the vodacom to repair, got a sms stating that its a warranty repair. Just received the sms saying i should phone for quotation. I phoned the repair shop and they informed me that they cant repair it and it needs to be replaced but i need to pay in R1100 for replacement. I can't understand why I should pay in and apparently according to vodacom they dont have warranty anymore and you need to have insurance. I can't see how this is a warranty issue i need to pay in to have it replaced i also know the Voda phone range had alot of issues. Hopefully someone can help me