Shocking - Do not know what they are doing

It is impossible to get MTN to fix any of their billing mistakes. I have been battling for 2 months now to get the correct billing discount reapp**** and for the refund to come through. This after having 5 different reference numbers and after 2 call centre agents assuring me that all has been resolved. It is the most difficult orgnisation to deal with as it is impossible to escalate anything or speak to managers or the right department.