Myslím, že neodbanují.
https://support.steampowered.com/kb_article.php?re f=4044-QDHJ-5691Steam Support cannot remove the ban on your account
Regardless of who was using your account at the time it was banned, the use and security of your Steam account is your responsibility.
Dej si do Google "hijacked account vac ban", je tam spousta odkazů na jednotlivé případy.
Napiš sem pak výsledek, jsem na to zvědav.