Billing issues 3 months running

I have not received the best service and without complaining too much I would appreciate it if someone can sort out my account. On the 27th of August I made an EFT payment of R1000.00 because my debit order date has never changed to the 31st of each month even though this was requested numerous times. The R1000.00 was allocated to the incorrect period (current balance) instead of the 30 day balance. My bill for 20.07.18 - 20.08.18 is R1147.53 which I was advised is only due end of September. Now I am getting sms'es saying my line will be suspended yet again if this amount is not paid... I expect someone to look into my account and give feedback urgently. I am not happy as your call centre and customer service departments just says I should pay and I am overdue. I also wish for MTN to place me back on Debit Order for the deduction to go off on the 31st of each month, as requested before. Please sort out my account as this is getting beyond rediculous!