Whats the reason for this ban?

[bilingual]

STEAM_0:0:198270

A week ago I joined a random server to play in. It had a weird title and it had some weird mod plugin. When I disconnected from this server to join another server... it kept bringing me back to that weird server. (Thats weird). I try to rejoin a different server, but it redirects me back to the other server. It was also playing some weird music as it was loading and on the server list. I exited the game and logged back into steam, but it kept saying the internet connection wouldn't let me connect. I haven't played for a week and I tried logging in to steam again and today it finally worked. I went into a KAC server and it gave me the ban statement. I checked the ban list and it says my steam is on the ban list. Can you please check what the reason is for? Also is it possible to be hacked by joining a CSS server?

[Kigen]

You were caught cheating on a trusted server middle of last year by KAC.

Sorry, but this ban is irreversible and will remain. If you wish to play on KAC protected servers again you will have to get a new Steam account.

~Locked