Unlisted or Unpublished does not mean Unobtainable. Any commercial entity to which you expose a phone number may sell, trade, or exploit it somehow.
The credit reprice frauds are known to get mouthy when challenged. DNCR access comes with FTC oversight and annual fees. The only "free" list is a stolen one. It's plausible that little missy gave you an angry lie, really a sentiment of open defiance of federal and state laws as well as your right to a quieter phone.