Ignoring nature of Telkom

I have tried to cancel my ADSL line at Telkom about 5 times now. Every single time I have filled in a form for the cancellation and every time Telkom confirms it will be done. However, Telkom just ignores the request. I have tried everything, I have done it via the call centre, via email and I have visited the store two times. The last time I have asked the lady for a proof of confirmation, at which point she responded rudely that it will be done an then asked for the next customer in line.