Deeply dissatisfied

My 5 month phone had a black screen. I handed in my phone at Telkom Somerset-Wes mall for repair as it is still under warranty. It has been more than 4 weeks and still haven't heard back from them, even check in and stand in a queue every week too hear what's going on and all I get is empty promises! I even phone the repair company in Kempton Park Bradian Logistics and according to them my screen is cracked and Telkom confirmed that it's not. I took my cellphone phone contract out at Telkom and nobody seems to care or sort out the problem. In the mean time I am borrowing an old cellphone! This is poor service