hi m8,if your account is hijacked contacting Steam Support, please provide the following concise information:
Steam account name.
The last e-mail address you used on the account.
You must provide verification for the account:
If you registered software purchased at a retail location, please include a digital photo or scan of a CD Key registered to your account. Please write your Steam account username on the quick reference card or CD Key sticker below the code in permanent ink.
more info here:http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_adp.php?p_faqid=197
i hope that can help you
Greetz Puma