Defective phone not repaired for over 11 days

My iPhone's wifi stopped working. It was still under warranty. I dropped it off for repairs at the Rosebank branch on 20 September. I called the repair call centre today (1 October) and was told the phone had only now been dropped off at the repair centre and was not even booked in. They would start looking at it tomorrow at the earliest. I use my phone for business and the replacement phone (which was not provided by MTN) is vastly inferior and causing massive inconvenience (online banking is not possible at the moment and other issues). I am disappointed that the phone just lay around for almost two weeks. I also doubt it is even repairable.