In my limited experience, you might have better luck talking to the agents rather than the company.
Had a letter through the door saying a collection officer had tried to visit, rang the company and they said they wouldn’t stop it, wanted me to fill out a form and send proof of tenancy.
Rang the guy directly and he just asked if I knew where the previous tenant was (I didn’t) then I never heard from them again.
Just don’t let them in if they do show up at your door.