Issue with closed account affecting credit report

I have a similar problem with Telus.  Except, the account was never ACTIVATED.  They were to send sims, but they never showed up, and so after spending hours dealing with Telus that (typically) never got anywhere, I told them never mind.   

And then the billings started.  And showed up on my credit rating (Mortgage renewal coming up.)  

I do NOT owe Telus any money - could not owe any money because the cellular account was never activated - but now there is some mysterious number showing on an open Telus account that is affecting my credit rating.

Literally days of talking to Telus have been pointless.  Talking on this board has been pointless.  'Trying' to talk to the 'support' from the moderators on the board has been pointless. Talking to the credit department has been pointless.  

One Telus guy even told me that "It is my problem, not his,  and if it costs me thousands of dollars in interest costs because of credit loss, that is not his concern."  I asked to speak to his supervisor, and he said " I AM the supervisor ... and what I say is final."  All the while his tone of voice was F off and D.  

The irony is that, though I would like to completely exist in a world without Telus ... sigh, last year we buried our Telus optical line across our farm at thousands of dollars of cost, and so we still have THAT small Telus INTERNET account ... and the idea of throwing that large expense away is SO frustrating, that we still have kept the Telus 'homeservice' account.  In other words, though we are not a cellular customer ... yes we are a Telus customer - and yet they treat us like this.

Unbelievable.