atrocious service from mtn

After various attemps to contact MTN on their call centre, they either cut you off or make you hold on for 45 minutes and still nothing, I have been trying to sort out a wrong biiling from their side but too no vail, in the mean time they just carry on billing you, they are quick to threaten you with cutting you off their network but they do nothing to sort out your problem, I have also sent them mails to their customer care centre but also no success, even if you go and talk to their sales branches they turn their hands up and cannot help you. MTN service is pathetic and I will be cancelling all my contracts with them their two year terms come to an end.