And where did you sell and buy these items? on Steam?

I'm sorry could you please say that again. All I'm getting is clicks and whistles here.

I sell my skin(from cs2) in community market and this mask from another game was purchased instantly in community market

your account is compromised
DO NOT TRADE
If you have access to the account

Steps to take NOW to secure the account:
1. Scan for malware https://www.malwarebytes.com/
2. Deauthorize all other devices https://store.steampowered.com/twofactor/manage
3. Change passwords from a clean computer
4. Generate new backup codes for your Mobile App https://store.steampowered.com/twofactor/manage
5. Revoke the API key https://gtm.steamproxy.vip/dev/apikey (there should be nothing in the APIKEY)
6. If points were stolen, do a password RESET to cancel the awards/points before they are delivered


Please review how you are logging into Steam or handling your log in information. You somehow gave them your log in information. This could of been due to the computer being compromised and redirecting to a fake login, or you using a 3rd party site to login to steam.

Originally posted by Vamp:

And where did you sell and buy these items? on Steam?

yes on steam

You aren't even remotely fluent in English. You need to use some kind of translator. Everyone is just guessing at what you mean.

If you need help with Account Security or Recovery, please contact Steam Support:

https://help.steampowered.com/en/wizard/HelpWithAccount

Please describe the issue in detail. The Steam Support will be very willing to provide relevant assistance for your facing issue.

I've locked the thread as appealing via those methods is your best route forward.