https://steamhost.cn/steamcommunity_com/discussions/forum/9/882959527688934488/
https://support.steampowered.com/kb_article.php?ref=7849-RADZ-6869&l=

Vac bans are issued for known cheats being detected on the computer while the account was connected to a vac server. VAC bans are delayed, what the account was doing at the time the ban was activated is unlikely to have anything to do with the ban.

Anything that tampers with protected game files is treated as a cheat regardless of it giving an advantage or not (skin changers, etc). Steam/Valve will not release any information about what was detected, that information will only help those that cheat and make cheats.

You are responsible for the security of the account and what is on the computer(s) the account uses. It does not matter who was using the account to cheat.

No one on the forums can remove nor investigate a ban. Only falsely applied VAC bans are removed automatically by the system at a later time.

This is not a ban appeal forum. You cannot appeal a VAC ban. Nothing you post is going to get the ban removed. There is an INFO link on your profile, click it and read what it tells you.

the VAC ban is correct and permanent. if it was falsely applied it would have been removed years ago

all accounts that have the same phone number on them will be banned at the same time if any of them earn a game/vac ban.