I've been stalked online. What I ended up doing was shutting down all of my accounts that he knew about. Really, that's all you can do.

In the future, never give your real name out to anyone you meet online. Create anonymous accounts that do not have your real name. This includes email, social media, etc. Maybe your name is generic, but mine is not. My last name is very rare and I could be found in a heartbeat if someone knew my last name. The only account that has my real name on it is Facebook, and I only add people as friends if they know me in real life.

Make new accounts, and carry your friends with you. Its a pain, but once you create these more anonymous accounts, you'll be safer from the stalker and you'll keep yourself safer from future online harassment.

As for legal ramifications? There are none. Or maybe there are some, but actually enforcing them is quite difficult. My online stalker wasn't in another country, just in another state. Fortunately changing my accounts was enough. (How could it not be enough? At that point he had no means by which to harass me.)

It really does suck when this kind of thing happens. People think I'm paranoid regarding my level of anonymity online, but this kind of thing is why I try to leave as little of an online foot print as possible, and stay as anonymous as possible.