Or you have a keylogger / malware that instead of logging you in it logs them into your account for them. I haven't heard of it recently, but a few years back people were complaining about this on wow.

The only way I've heard of getting someone off your account is to put a token on it, but since you already have one that won't work. If I were you I'd use their live chat / phone support. You'll probably make it through the wait before they close for the day.

To this end, I would actually do both live chat and phone support at the same time. Just in case one errors out.

FYI, you might end up getting suspended even though you tried telling them it wasn't you. So assume you'll be waiting 2ish weeks if that happens to get it back unless they've drastically increased their investigation time.

Good luck with it.