Help with Telkom cancellation and NuDebt demand

Together with many other Telkom clients, I too am at my wits end and have now received a letter of demand from NuDebt. I cancelled my Telkom line 31 May 2018. They told me I need to first cancel the line with my ADSL provider. This was done a year previously, so had nothing to do with them. I get an sms to say case resolved. I try again and have to wait as the system won't allow me to log in again for a cancellation as it says "case resolved" I eventually do so again and write in the comments explaining I don't have any Telkom ADSL line and attach my Service Provider invoice clearly stating NO ADSL line. A year down the line with no cancellation but continuous billing, but many calls, visits to their shops and emails, I now get a 24 hour notice of demand Has ANYONE got this right ?? Does anyone have a contact, email or department that have assisted them ?? Seems like there are many clients in this exact situation, and we are clearly just "lost" in the system - I am not prepared to accept this diabolical service, nor pay for a service I have not used in a year...HELP HELP Thanks a lot