Incorrect billing since July 2015

I cancelled my landline in June 15 and are still invoiced for it and debited my bank account.<br> Telkom mobile, cancelled a contract Sep 2015 still not finalized. New contract incorrectly billed.<br> After hours and hours to the call center and visits to the branch my situation is getting worse and my bill increase every month. I'm going to stop my debit orders and refuse to pay any interest due to overdue accounts. I will however pay all fees rightfully owed to Telkom. I need sufficient assistance as soon as possible!!!