[[Some buttons on the official site are a bit different on US version, so bare with this EU player ]]
Especially when doing much illegal stuff like buying/selling accounts, sharing accounts etc, there is a high chance you will be hacked sometimes. So, what to do after that?
For this guide, I will assume you are the real owner and not some lousy hacker, and thus you got all info.
I. Try to get your account back yourself:
If you see you are being hacked, go to the Official World of Warcraft site (EU site). Go to account management and try to log in. If you are fast enough and the hacker isn't quite smart, he hasn't changed your password yet and you can change it back to buy yourself some time.
If you are logged in, change your password, your email and then try to put Parental Controls on: this makes sure the hacker (if he isn't logged in yet) can't delete/sell your stuff yet, which makes the whole process a bit easier.
Then scan your computer. This is vital, since there is a chance you have a keylogger. If you do, delete it. If you don't, you probably got phished or so and you're quite safe if you changed all your info.
What to do if your password and email are changed already:
Go to the site and click on "Change your email". Enter your account name and then follow the instructions. If you don't know your Secret question and answer, fill in your CD key instead. If you don't have that, you're screwed, but don't worry; I'll come back on that later!.
Now your email is changed, good. This allows you to retrieve your password and do the same as I described above.
II. Get Blizzard to help you retrieve your account.
However this process takes longer, it is most of the time the best way to get your account back for sure.
First, go to this webform (That is the EU version, change url a bit for US version).
World of Warcraft -> Account Security -> Fill in everything and click on Submit.
If you don't know your SQ/A, fill in your CD key. If you don't know that one, make a picture of your ID and upload it there. And if you even can't do that, fax it (details are at the webform).
Now just wait, and eventually you (most likely) get your account back. If you are still missing items or gold, make a ticket ingame and the Game Master will try to reimburse your items.
-Aldun