POOR CUSTOMER SERVICE - QUERY NOT RESOLVED SINCE FEB 2019

The customer care service at MTN is so DISAPPOINTING AND POOR. I have been a customer of MTN for many years and have recently upgraded my contract in February and have been billed an incorrect amount (a higher amount) since my contract was upgrade. I have called the MTN customer care line countless of times. have been given countless reference numbers to try to resolve my issue but each time the query logged is either an incorrect query or I get told that they cannot assist me. I have been told my query has been "resolved" via sms and when I call in to double check that it has in fact been resolved, a call center agent, by the name of Kate Khoza, tells me that "resolved" means that the query has been escalated to another department and therefore my query has not yet been solved. I have also tried speaking to the call center agent who assisted me with my upgrade, Naydene Emanuel and she insists that she cannot assist me and that I must call the general help line of 135. This is such poor service on MTN's part. I have been unable to speak to any managers because the call center agents either cut the call or put the call on hold indefinitely until I have to end the call. On two occasions, I was told twice that the manager will get back to me but no one has done so yet. Does MTN just hire any person to work for them even though these individuals clearly have no idea how to handle any query and are evidently not qualified? I am very very DISAPPOINTED and highly exasperated that despite me trying to resolve this issue from February, nothing has been done.