Bad service from Vodacom

I bought a cellphone on the 17 of october on vodacom,within 2 weeks the screen kept going black when i was using the phone.I took it back to jet and the booked it for repairs,it's been over a week and i haven't recieved any correspondence,i decided to make a follow up,then they told me that my claim was marked unpaid.How come you sell me a damaged phone and then refuse to repair it afterwards?where am i supposed to get money to fix the phone or buy a new one?Vodacom you are very disappointing and i wouldn't advise anyone to buy a phone under your name if that's how you treat your customers!!!