As far as I can tell, they haven't sued you either. In fact, I don't think you've even received a letter from their lawyers. All that's happened is that someone

As far as I can tell, they haven't sued you either. In fact, I don't think you've even received a letter from their lawyers. All that's happened is that someone at FB had threatened you. Personally, I think they're full of it. I'd at least wait until you get an actual letter from their lawyers before making any decisions.