[Fey]

Stop trying to defend yourself. You did NOTHING wrong, so stop trying to defending it. If they keep bringing it up mention that 'Hey, guess what, it was a misunderstanding and it might be time to move on.' If they can't move on, well other people involved will start to see that you're not doing anything wrong, and that they're just beating a dead horse(for lack of a better analogy). I do agree that discussing it would be best, but they sound like the sort that won't actually have a discussion they'll have an argument.

As to the convention, short of them being the people paying for it/running it there's not much they can do. If they do try to pull something approach another staff member and tell them you're feeling harassed. Trust me, no convention wants that hanging on their neck. After all they're out to make money by encouraging people to spread the word and come back. You can ask for them to keep your name out of it, but even if it does get back to them it'll be their head on the chopping block.