Telkom keep on billing me for seriveces cancelled

We cancelled our Telkom line and ADSL for 29 May 2015, the services have been cancelled and there is no service. But still until 3 August 2015 Telkom is deducting money from our bank account via debit order. We have called them and they promised that they will refund us and they will stop billing us. this was during July 2015, but no luck, money still being deducted from our bank and no refund from Telkom. Please help, if you call Telkom you are on the line for more that 40 min before you can speak to a consultant and even then there is no joy from them.