Non-existent customer service

MTN billed me more than the usual monthly subscriptions. I tried the customer care call centre over 10 times. I was kept waiting for an average of 20 minutes every time I called and on the two lucky occasions that I got to speak to an operator, the call was dropped partway through the conversation. The enthusiasm of the call centre agents left a lot to be desired. I sent an email to customer care on the 2nd April but up to now I have heard nothing from them. I went into an MTN store in Tzaneen and I was told by a staff member there that she is fed up with the call centre as they also have the same problem in getting through. MTN expects me to pay for an itemised bill when it is them that have overbilled me but cannot offer a satisfactory explanation. MTN's customer service is pathetic and non-existent!!!