Super irritated with MTN!

I've been experiencing serious billing issues with MTN on numerous occasions. One of the events I made a cash payment at an MTN store, which MTN did not allocate the payment to the account and suspended the line. I had to then call MTN to resolve the problem. Most recent occasions MTN said they debited my account, which they did not in January, I even spoke to a supervisor that said that is true and MTN is at fault (it's on a recorded conversation). He said he would send the matter through to billing to determine what the problem is because now the account is showing in arrears of an amount of R300-something rand. Which I ended paying today because they've suspended the line 3 times in less than 2 weeks becuase the problem was not resolved. So the supervisor admitted on a recorded phone call that MTN is at fault yet I'm still liable to pay the "arrears amount" which has been caused by MTN's consistent issues. On a separate occasion, MTN sent a message stating that they are going to suspend my line if the account is not paid in 2 days, this was on 28th of the month when my debit order is only payable on the 1st/2nd of the next month. I'm absolutely appalled by this situation and so frustrated with MTN!