Escalation required

I had an ADT Security account at an old address over 15 years ago; the house was built by a neighbour who then moved to a house across the street.  My thinking is that we set up a new account but that it was somehow linked to the old home owner’s account but because of the length of time that has elapsed, it’s hard to know what happened there.  We then built a house down the street and moved the security system with us; then ADT became Telus and I got divorced, so moved the account into my own name (versus what I believed to be my husband’s name).  I recently moved again and closed the account in my name with all fees paid (to my knowledge and in my name).  Two weeks ago, my old neighbours contacted me to let me know that their credit score had been impacted by a $280 charge from Telus that was somehow linked to my addresses and my name.  We have since spent HOURS contacting customer service about this, attempting for it to be escalated, but no one can understand what has happened, nor are they able to remedy the situation because it has gone to a collection agency and - according to Telus law, once that happens, it is “out of their hands”; however, according to my neighbours’ lawyer, if we pay the collections agency, the black mark on my neighbour’s credit rating remains. 

I am really at a loss of what to do next outside of taking to social media or taking legal action (which has already been explored by the other party involved here - as well as police enforcement).  Wondering if there is anyone else I can call to have this revoked from the collection agency, so I can pay the outstanding fine for my neighbours and they can have this removed from their credit rating???