No backup codes and no access to authenticator app

I have a free account that I'm locked out of. When I log in, I'm asked to use an authenticator app, but I don't have a Zoom code in my current app. I do not have access to any back-up codes and so am effectively locked out of the account. To be honest, I do not recall even setting up 2FA on that account. In any case, now I cannot access it—how can I gain access again?