Defective phone

I wanted to cancel my contract with cell c and they convinced me to take a new phone, so I did. The phone was delivered on 1 December 2015. I received the phone Samsung J1. It didn't have the volume buttons and sim slot 2 was defective. I called customer care within 7 days and they said I must go to any cell c branch. They failed to fix it. I called back and they said they will collect it. It was collected on the 17th of December. I called them and they said I was not suppose to use it, which I wasn't informed. They say they waiting for new spare parts up until now. I still don't have a phone and it was suppose to be a brand new phone. When I call they give me the run arounds. Nobody told me not to use it while I was waiting for the to collect. I was given OBF No. 169378. Please cell c resolve this because I don't have a phone now