Monthly debit on a non existent debit order

telkom is claiming my telephone account from a non existent debit order. I have never signed a debit order for Telkom. I have phoned, sent e mails - but not even a reply. I am paying a penalty for the past 5 months of R180.00 per month. I would like to know if there is a responsible person in telkom that might be able to sort this out and credit me for the money just taken.