Unfortunately, I've had my work cut out for me with online imbeciles too. There's not much you can do besides getting a new alias, because things that happen in a virtual environment are hard to report, unless you know who the person is who is pestering you. Even then, local law enforcement rarely act on reports and if the person lives overseas, expect to fork out a lot of cash finding a lawyer. I know it's hard to stop Internet harassment completely, as I also tried to pinpoint who was causing this abuse, and gave up hope. I've been put through stressful situations too.
One guy follows me around forums, puts my videos on torrent sites, edits Wikia pages about me, adds films I'm in on other databases, and harassed me on a forum a few months ago, where I was even unfairly banned, just because he asked them to. Without any moderators, the administrator just got rid of me to shut him up, but he returned anyway, because he probably suspected I'd try to post there again with a different account. He knows where to find my videos even if I don't publicly list them on YouTube, because of where they are embedded. He knows what things I like to talk about too, which is why he found me on so many other sites and started harassing me even more. Well, I know what state he lives in, but I'm not in America. He lives in New Jersey.
The police need to act on complaints, every single time something occurs, because small amounts of abuse can quickly expand.