This is automatic message:
Good day! Steam User marshmallow_616, Your account has been banned because we detected several virus and illegal programs that is damaging steam server on your account. Purchasing, gifting, trading, cd-key activation, and Steam Community access will be disabled. We suggest you to move all of your tradable items to a different steam account until we resolve this issue or else they are going to be automatically permamently removed once the ban appears on your steam account.

You got reported by many players and we have to limit your account, our decision took 2 months, we analyzed all your activity and reports. Once the ban is implemented, we will send an overview of the report on your email denis_lim98@mail.ru.

When the software detects a cheat on a player's system, it will ban them in the future, possibly days or weeks after the original detection. It may kick players from the game if it detects errors in their system's memory or hardware. No information such as date of detection or type of cheat detected is disclosed to the player. After the player is notified, access to online "VAC protected" servers of the game the player cheated in is permanently revoked and additional restrictions are applied to the player's Steam account.

The decision is permanent and it can't be undone.

If I'm VAC banned what does it mean for my account?
Account will be useless. You cannot play on any valve secured server nor trade any items once the ban is implemented.
Note: Users are not VAC banned based on alone reports. Other factors are taken into account before VAC bans are issued.

All messages are read and reviewed by the VAC development team.
If you have any questions, type in this chat, our support manager will answer as soon is possible.