I do have the twitter handle. The problem is that they are using their Twitter name as the same as my trademarked name. So while my twitter is: twitter.com/ActualTrademarkName their twitter is twitter.com/NotRelatedToTrademarkName but what they call themselves on twitter is ActualTrademarkName. Does that make any sense?

Agree in preventative brand confusion! Unfortunately, whenever I conceptualize a project, I always have to look at other sites to register the usernames, for exactly the OP's reason.

Twitter, YouTube, and domain name. I never do Facebook though (personal abstinence from it).