Faulty phone & unprofessional staff

I bought a phone sometime in June from the mtn shop at Rosebank and for some reason it just ceased working after about two months. I returned the phone in it's box to the same shop were I bought it on the 3rd of September and they took it and told me that they'll send it for warranty assessment and it would take a few days. I returned to the shop on the 8th and was told that they're couriers RTT had sent the phone to the wrong place and they're trying to get it back, I understood that it was a mistake and left the shop for them to rectify. I went back again on the 14th of Sep and was told the same story that they still haven't received the phone from the wrong place. Now my problem is I'm been thrown from piler to post. They don't give feedback so unprofessional and now they tell me that the area manager Sharon knows the problem but can't fix. I mean I haven't had a phone for 16 days and the worst part is they don't even know where the phone is. I expect better service from MTN and it employees considering that I ported from another network to join them. A little bit of feedback goes a long way, instead I'm left frustrated and without a phone. Shame!