Over charging from Telkom again and lack of service

I have had an issue with Telkom since May that they have said they resolved 4 times but still havent. Was on ADSL and they offered me to over to fibre. I said I would as long as they cancelled my ADSL. You are still charging me for BOTH. Even after numerous occasiionsmaking contact and they said had been resolved. I said would not pay for both as this is Telkoms mistake. Telkom has now handed me over to NuDebt collection agency to pay for for something I shouldn't have to. I see this has happened to numerous other people aswell with Telkom has have recieved replies from other people regarding same thing. Why should anyone get bad debt for Telkom mistake. Also NuDebt say I signed and asked for it in writing well this is something I never did anyway.