If your account is locked or you suspect it is stolen, we’ll need to verify that you’re the original account owner:
Providing Proof of Ownership
https://support.steampowered.com/kb_article.php?ref=2347-qdfn-4366
For all other questions, you may be able to resolve the issue yourself by searching the FAQs on our Support site:
https://support.steampowered.com/
We thank you for your patience, and will help as soon as possible.