Telkom Useless Service

I had a LTE contract which was cancelled after the contract expiry date. It was cancelled at the walk in office twice, once online and once by e mail. I changed to fibre during this time and never used the Telkom service after cancellation. Now I am threatened of being blacklisted and all sorts of things for not paying my Telkom account. It seems that their accounts department is useless and there is no communication of cancellations to the people involved.