faulty phone and bad service

I have new contract with cell c and only have the Phone for a week and It broke could not switch It on and It was collected for repairs on the 2nd of September and received the Phone on the 21/09/15 and the 22/09/2015 It gave the same problem ,i called the head office and was transferred from department to department with no help and eventually they some one came and pick up the Phone again.i have sent email demanding a new Phone as It's unfair for me to pay for the Phone that i don't have and i have not yet received any feedback from