Have you tried logging into a different region? Pick another simulator such as Waterhead or something memorable and under preferences change your setting to allow you to log into other locations.
If you're still locked up with the sim ghost, and cannot contact the sim owner or if it's one of LL's sims, submit a ticket to LL and someone should drop in and restart the simulator for you.
BTW generally the ghost isnt linked to the system fully so most IMs and messages will go to Email if you're set up that way. Not sure busy status works with a ghost though.