This account violated the Lichess Terms of Service

means literally that person has cheated or smth else

u also cheated

Same with your own account

that is very strange
must be a coincidence
violating the terms of service can also be aborting lots of games
@MissionVao

@Checkers_captian Yes that's true @MissionVao if you don't know when you cheated or why you got banned,you can appeal in lichess.org/appeal