MTNs pathetic customer service

I have 4 contracts with MTN and upgraded one of my lines on the 25th November. I received my bill on the 12th December only to realize that I was charged pro rata and advance charges for all 4 of the lines instead of just the one upgraded line. I have been calling MTN since the 15th and not one person could assist me. I received pathetic service from each of the reps i spoke to. Numerous escalations were logged and sadly the escalations team could not identify an issue with their own billing systems and sent back feedback on the tickets stating that the billing is correct. I further spoke to 2 managers who promised me call backs and still nothing materialized. Everyone seems to have a 'dont give a damn attitude' and passes the buck to the next person. I am frustrated as i am being billed almost R3600 for a bill and not one person can help me with this. I am so tired of calling MTN and being pushed around. I will never ever recommend MTN to anyone. If I could, i will cancel all 4 of my lines with them.