Poor service

I ordered a new cell phone from MTN Direct and received my phone on the 31st of December. The phone started giving problems on the 1st day. I contacted MTN several times and they did admit that the phone were faulty and they needed to recall all the Sony Experia M5. The lady said the she will get a courier to pick it up from me.Nobody has come for 2 to 3 weeks and I called many times and they said they will get Nonhlana to call me back. Ever since that time she did not call me back. I must have called the call center about 15 times this month and the guys say that they will mail her. Every person I spoke to said that they will mail her and she will contact me. Now I have this faulty phone for 2 months with nobody even calling me to collect the phone. I am paying for something that I cannot use and it is not even a problem on my side but MTN's. I am very disappoined with the service.It is having an impact on my work and family because I cannot call out or receive call sometimes. It works when it wants too.