Really unfortunate and I'm sure extremely frustrating! I would definitely appeal to the ombudsman.. it can't hurt. It is possible you were denied because you have or perceived to have associated with person(s) who are flagged in some database... in which case you'd never be told if that's the reason. I'm grasping at straws here... from what you've described about yourself there's no good reason for the denial. Lack of international travel isn't a criteria to deny someone.