Billed for ADSL account I cancelled 5 months ago.

I had an ADSL account last year. I then moved houses and requested for the account to be moved to the new location. They got back to me a month later and told me the new area I'm moving to has no infrastructure. I then requested that it be cancelled. Since I was still being billed, I filed a dispute on the amount then I app**** for an LTE Advance 100GB a month contract which I received. No one has contacted me regarding the dispute until now. I never received any invoices for the LTE account either. I kept going to Telkom Main Street and Telkom Southgate to request for the invoice for my accounts. They kept reprinting the same ADSL account. Yesterday, I receive an email from a very rude Telkom employee demanding that I pay R9,253.38. I ask him to explain the debt so we can reach an understanding and negotiate. That was followed by threats to list me and take me to court because apparently, \I'm not understanding the gravity of this situation\". How is it my fault that my ADSL account was never cancelled, my dispute was never attended to or that I was not receiving invoices for the LTE account?"