Yes, of course. Refute them if you can do it without being a dick. Ignore them if you can't. Even if you never interact with them directly ever again, they'll

Yes, of course. Refute them if you can do it without being a dick. Ignore them if you can't. Even if you never interact with them directly ever again, they'll talk to other people, and you don't want to give them fuel to burn you with.