Nastuduj tohle:
https://support.steampowered.com/kb_article.php?re f=1266-OAFV-8478
https://support.steampowered.com/kb_article.php?re f=2347-QDFN-4366
https://support.steampowered.com/kb_article.php?re f=2347-QDFN-4366

Na stránkách Steamu se píše:

Immediately Contact Steam Support about the lost account

Provide the following information:

1. Steam account name for hijacked account
2. The original contact e-mail for the account
3. Select “Account Questions” as the category and “Hijacked or Stolen Account” as the subcategory.
4. Proof of purchase for the account as outlined below:
o If retail software is registered to the account, attach a digital photo or scan of the CD Key registered to the account. Write the Steam account username on the quick reference card or CD Key sticker below the code in permanent ink.


o If a game was purchased through Steam with a credit card, please provide the following:
+ The Card Type (Visa, MasterCard, Discover, American Express)
+ Full Name on the Card
+ Expiration Date
+ The last four digits of the credit card number - Do not provide the full credit card number
o If a game was purchased through Steam using a PayPal account, please provide:
+ The Billing Name on the PayPal Account
+ The full Billing Address on the PayPal Account
+ The PayPal PayerID
+ The Invoice ID and the Transaction ID

If any other type of payment was used, please explain this in the support ticket.