Steam Sales - Purchasing and billing FAQ
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Originally posted by PollaroiD:

please help me!!!!! i didnt make any purchases in dota 2 but in my purchases history i made purchases and spent around 7,000 yen

Sounds like someone has access to your account.

Do all the following steps to properly secure your account.

Scan for malware https://www.malwarebytes.com/

Deauthorize all other devices https://steamhost.cn/twofactor/manage

Change passwords from a clean computer

Revoke the API key https://steamhost.cn/steamcommunity_com/dev/apikey

Generate new backup codes