Easily... it's just a contract - anyone can contract a debt collector.

A reasonably one would require proof including the original contract, but, big companies like this are so automated, they have their processes down to an art.

It will pretty much be an export of unpaid debt gets sent to a collection agency. The collection agency will try to hound people as much as possible to pay.

People who don't pay may get taken to court and the debt collectors will either win by default, or, the person will show up, say they haven't been a customer and win with ease.

Also, any reasonable debt company would drop immediately upon sending proof, but, so do a lot of liars, so it's a hard one, but the law is on the customer's side.