Earlier quoted context omitted.
For future reference, just tell the vendor "I did not authorize this charge. Please refund me". Don't engage them further. When that call fails (or, if they don't pick up the phone in a reasonable amount of time), call your credit card company and say "I want to issue a charge back". They'll ask if you tried to work with the vendor. Answer "yes", full stop. There should be a phone number associated with the charge on…
And what if they then send you to collections? Now you’ve got bill collectors after you and your credit affected.
Collections officers can't try to collect disputed debts, so they immediately left me alone.
Then, I spent over 24 hours on the phone with AT&T, and eventually paid them a bit under a hundred dollars that I didn't owe them. There was no credit report ding or harassment from the collections agency, at least.