8ta No Reception, MTN roaming do not work!

Hallo Peter <br> <br> I have a contract with Telkom mobile service provider 8ta. There is no to very little reception in Constantia Park, Pretoria where my offices are located. According to them your carrier will switch to MTN where there is no reception. This does happen and I then do have reception then but I cant make a call or receive a call if I don't restart my phone, iphone 5. It very frustrating, my client cant get hold of me! I am loosing clients and income due to this problem. If I knew there were so many problems with there roaming or reception I would not have move my cellular contracts to Telkom mobile.