Unauthorised debit order activation

Secured a contract via Telkom's partner: Mondo which the Sales representative clearly stated and reconfirmed to me was for a set 24 month period. I notified Mondo on 4 May 2017 of the clear indication contract is to be terminated at the 24 month period. Even though contract terminated, Telkom continued to bill me R99,00 per month for 5 months without any legally agreed contractual arrangement with me. At 2 months of trying to obtain contact with Telkom via online chat, email, telephone, I managed to telephonically make contact and obtain a cancellation form but I still have not had the 5 x R99,00 refunded to me and my email enquiry to why this has not happened goes into a deep whole, ie no response from Telkom. Even after acknowledge the cancellation form, Telkom still proceeded to debit my bank account.