Cannot get Telkom to cancel our line

I have been trying to cancel our charity's office line since May - we lost our sponsored office and had to move out on short notice. Phoned cancellations (after holding on for more than 30min) was told to fax cancellation letter. Also ask them to block the line for outgoing calls. Tried to phone again this morning. Hung up after 22 minutes. Tried to send the fax again - but just says Line is Busy. Bad service from Telkom is costing our charity money - money that could have been used to help abused children. At time of writing this complaint, I have had no luck successfully communication with Telkom. One would expect much easier systems for a technology company - not holding on forever, not getting through to fax lines and not getting any results. The number in question is *** - if anyone at Telkom can assist other than those who cannot!