Impossible to cancel a service with Telkom... such poor service from this provider!

For the past 18 years, we have had three Telkom VSAT Spacestream lines as well as a internet connection. Two months ago, the system simply went dead and there was no service avaiable at all. I tried numerous times to log the fault, was passed from one person to the next. Finally after getting now where, we went into the Telkom office in Cresta Shopping centre JHB and spoke to a consultant at the counter. The consultant looked up the account details and telephone numbers and said that there "is not such telephone numbers on the system, they must have been deleted or discontinued". We were then told that the service we had from Telkom was in fact no longer operational and that we must get hold of another service provider... That is no problem, I was more then happy to get an alternative service provider and be done with Telkom for once and for all! However it is impossible to cancel the account which is still be debited off the bank account each month. I have filled out all the cancellation documents and sent them to the cancellation email address as requested and heard nothing back from anyone. I then called Telkom and was told that the cancellation documents have not been logged and that I should send them onto the call operator directly and she gave me her direct email address. I have tried this twice now and have got no response from her as well... What a nightmare to cancel a service with Telkom. If I have no further luck from this post, my only other option is to go into the bank and block the debit order. This is extremely poor service for a customer who has been with Telkom for over 18 years!!!