You’re in Australia?
If anything like that happens again, or something like you purchase a second hand car but weren’t supplied the signed registration paper / no receipt… need a day off work due to illness but don’t want to pay to see a doctor / telehealth etc etc
You can statutory declaration, a written statement you declare to be true, many professionals can witness them, teachers, dentists, vets, engineers, mostly anyone who’s practice requires they be a member of a professional organisation.
If you were to serve such to Anytime Fitness, either before you intended to leave serviced area, or any time prior to them selling the dept to recovery, they are obliged to cancel from the date they were served or the date you state in the declaration.
A Process Server can hand them the declaration, or you can in person, or registered mail to head office.
This also tends to work for parking ticket fines issued by private car park operators whereby you make a reasonable offer for the time you were parked there—eg ten minutes prior to the first ticket, so one whole hour of parking as a reasonable counter offer to their punitive ticketed fee—though these all tend to be electronically gated these days so mostly moot.
I tend to do a higher than average level of minor civil disobedience type behaviour, and tend to find it quite enjoyable arguing my point knowing I’ll typically win the argument.
Yours truely, Mr Middle Age Curmudgeon