Non-existent service delivery

I am at my wits’ end about poor service delivery from Telkom as I have been trying to close a business account for months now, without any result, while still receiving monthly invoices for services not delivered. The background is as follows: 14/02/2017: Request for moving of business line from old address to new address effective 01/03/2017. 15/02/2017: Order number ********** 25A is logged. 28/04/2017: Visit Telkom office as the line still had not been moved. Technical problems cited. 24/05/2017: Dispute ********** 8 is logged for rental credit as invoices were paid dutifully every month without any service rendered by Telkom. 09/06/2017: Account credited on paper. 14/06/2017: Request for closing of account as Telkom is still unable to provide the service. 09/07/2017: New invoice received – still no service from Telkom. 09/08/2017: New invoice received – still no service from Telkom. 15/08/2017: Visit Telkom office to close account again – advised to send another e-mail. 16/08/2017: Received e-mail from SMBS Retention Centre that account will be closed within 21 working days. 13/09/2017: New invoice received – still no service from Telkom. 13/09/2017: Send cancellation details to SMBS Retention Centre again, received reply account will be closed. 12/10/2017: New invoice received – still no service from Telkom. Between February and October 2017 twenty-nine (29) e-mails on the issue were traded with Telkom on the issue. However, the technical problem could apparently not been resolved. Telkom has not provided any service to me from 1 March 2017 to date, and I therefore do not owe the company any money, but they still send monthly (accumulating!) invoices. To the contrary, Telkom still owes me R1,589.68 credited on 09/06/2017. Does anyone have advice on how to get rid of Telkom?