Well, let's just get it out of the way right now. You can't hide from him, so don't bother. If he messaged you from another account through your faction he can also see which zone you are in at all times. Don't bother running.

You probably have only 3 legit options here. First, you can try to communicate with him again and maybe talk things through.

Second, I play a pvp server, and I know that camping people will piss off a lot of GM's and they certainly do punish people for extraordinary camping. Four days certainly constitutes extraordinary. You can try repeatedly reporting him for harassment until you get a GM that feels like letting you enjoy the game.

Finally, and the option I would take myself, is to fight fire with fire. Camp him back. Ask for help in pvpchannel, tell your guildmates, get some guildmates, ask for help from a few well know world pvp guilds on your server. They'll probably leap at the chance since world pvp is barren atm.

If that spoiled little baby gets spanked enough, he'll leave you alone.