Credit Record Ruiners and Subscriber Abusers

Cell C keeps debiting my account but I have made my phone paid up. I settled the phone inJune already with d amount that they gave me . I have called them to cancel my phone contract and deactivate my sim cards as i have lost one of the phones and lost the Sim card. When I call the complaint department i got transfered to the subscription department , and dt depart can not resolve my query then they transfer to cancellation team. Cancellation can only tell me that they will only terminate my contract in October when the contract expire. My problem us why are they debiting my account if the simcard are deactivated no one is using the subscriptions and the phones are paid up. What am I being billed for?? No seems to answer me