Cell C Bad service - Unhappy customer

After calling Cell C and telling them that when the contact ends the following month and I do not wish to continue because I'm currently under debt review. They still went ahead and loaded services on two of my sim cards for three moths. Now this is affecting my credit record and I have called them serveral times but no luck. I have debt collectors calling and demanding I make payment.... for what? when the contract has expired? how do you continue loading data without my consent?...... I strongly discourage anyone from signing anything with these guys.