Incorrect billing for September

I have sent notifications via Vodacom's website to their accounts department twice since receiving an incorrect invoice and statement dated 3 September. STILL NO ONE HAS MADE CONTACT WITH ME SINCE THE 3RD OF SEPTEMBER, what shocking service. This is now my 3rd attempt which I am logging on Hello Peter as it seems this is the only way to get their attention. My invoice and statement for September ARE INCORRECT!!! I have informed Vodacome 3 TIMES NOW that the debit order that comes off at the end of September is going to be returned as it is incorrect and I AM NOT PAYING IT UNTIL THEY CORRECT IT. Please can Vodacom contact me to sort this out - I want to pay but refuse to pay an incorrect billing which is much more than the agreed monthly amount.