Bad Customer experience and incorrect billing by MTN

Last month i wrote a review on the extra promotional charges from MTN. I applaud the immediate response saying it would be corrected however, it has not been corrected. I was charged R863 on the 1st of July, R1082,09 on the 4th of July and now again R811 on the 2nd August. This is after changing my deal\package to a lower amount of just a data package at R241pm. I know regret not cancelling my contract. This is surely a breach in agreement and exploitation of ones personal\banking details and the ability to debit any amount you wish.