You could try this https://help.steampowered.com/en/wizard/HelpWithUnknownCharges

They usually dont do anything for stolen wallet funds as your accounts security is your responsibility....but still it doesnt hurt to ask..

Also do the following steps to make sure your steam account is secure:

1. Scan for malware https://www.malwarebytes.com/
2. Check that the email and phone number on the Steam account are still yours.
3. Deauthorize all other devices https://store.steampowered.com/twofactor/manage
4. Change passwords from a trusted/clean device.
5. Generate new backup codes for your Mobile App https://store.steampowered.com/twofactor/manage
6. Revoke the API key https://gtm.steamproxy.vip/dev/apikey (there should be nothing in the APIKEY)

Accounts are phished not hacked.

You gave away all your account details.

The account name, the password and the KEY to the door, the Steam Guard Mobile code giving them access to the account.

How? by either logging into a known scam site or sites, tailored malware on your PC, the vote for my team scam, you have a pending ban scam on Discord, free knife click the link etc.

How does Steam (a program) know it is not you when all the account details are correct? It doesn't, therefore any action taken on your account is seen as you doing said actions.

The alternative is not plausible:

1) Someone would have to "GUESS" your account name from "millions of possible combinations".

2) Next they would have to "GUESS" your password from "millions of possible combinations" and then match it to your account name with "millions of possible combinations".

3) And finally they would have to "GUESS" the Steam Guard Mobile code "which changes every 30 seconds" to match both your account name and password to then have access your account.