Continuos Repairs

I sent my phone in thrice in the sapce of a month for the excat same fault and the third time after they repaired it I did not want the device as clearly it must be a defect if it gives the same problem. They once again sent it to the repairs centre and after emails i sent a consultant was supposed to contact me which never happened and after another three weeks i decied to contact them and all they said to me was that they repaired the phone again and the motivation for a new device is rejected. Nobody has consulted with me and I must say the service was PATHETIC!!!! The worst of all is that the phone was purchased on the 05/02/2015 and by the 20/05/2015 it went in for the first repair and after waiting three weeks I had it a week and it went in on 12/06/2015 and then again waited three weeks and had it a week and it went in again on 22/07/2015 for the exact same problem clearly it is a defect!!! Vodacom is disappointing.