Overcharged for month to month contract

Cell c is charging me 2500 for a month to month contract which they cancelled first month when they didn’t manage to process the credit card and instead of calling me for payment or correct details they have just handed over to attorneys and amount of 2500 cannot be correct for a month to month contract I am only willing to pay what is due but no one can give me proper answers. I would like a manager who can make decisions to contact me.