Comment by timr

Meh, good luck going to the manager of your local instance of Marriott or Hilton or Hyatt and getting a corporate-level ban lifted. They're going to tell you that it's above their pay grade, and to contact HQ. HQ will ignore your attempts to contact them unless they come on the letterhead of a law firm. Maybe you can get a ban lifted if it was imposed by the instance, but even then, they're probably just going to tell you to go to HQ.

It doesn't matter if it's SPG or AirBNB: when you're fighting with a large company that (you believe) has made a mistake, the best/only path forward is to get a lawyer involved.