God, I’m shaking. Funny, the first toon they transferred off was a 78. They stripped down one of my 85’s and an 83. I’m logged in both accounts now, and on hold waiting for a rep both on phone and in game. WTF. 
Mine got hacked a year or so ago, but I was lucky. They apparently were spamming /trade and got me suspended, before they had done anything to any of my toons or my gear. When I got back in everything was fine except some of my interface settings had been played with.
Although just last week I was using WowArmory for mobile devices and brought up a list of my toons and found out I had two level 1 toons on different servers I had never heard of. They must have been created especially for spamming.
That makes sense. I have a lot of looking to do. I really didn’t expect to wind up sobbing on the phone, either, but that happened. I have so many toons. I have to go do some research on all my realms.
By they way, if you’re not using the Authenticator (and I assume you’re not), don’t put it off any longer.
Yup. Just ordered it.
Don’t freak out. It will take a long time to get through to a customer service rep by phone, but once you get through, he’ll get everything sorted out pretty quickly. Be nice to the service rep. You’ll get all of your stuff back, and might even wind up with some extra stuff (the hacker had bought some gems and stuff with my gold but didn’t move them before he got locked out. Do get an authenticator if you don’t have one already.
I was very nice, except the crying bit. I think he felt bad. But man, I got my 78 back quick! With $12k gold on her. I didn’t realize that was the sum total of gold I had (or maybe that included the gear from the naked toons).
I only play a couple of hours twice a week these days, but I’ve been logged in ever since he got me squared away. I’m on my 71 dwarf hunter, doing dailies so I’m not completely broke. 
That happened to me, about a year ago. Cleared out my highest level guy completely, dumped the cash on all my other characters, and flat out deleted one dude.
Inside of a week, I had everything back, plus a good chunk of change that I guess Blizzard dumped into my account by way of apology.
The cherry on top was, a couple days later, a letter shows up in my mailbox from someone I’d never heard of. “Thanks for the gold!” it says. Forwarded that one on to Blizzard as soon as I got it.
Do you have an authenticator now?
I don’t play any more.
Ah, okay. I play probably 15% of as much time as I used to spend in game.