That's great.
Now, report the account and move on with your life.
Public accusations and/or reporting is not allowed.
https://support.chess.com/en/articles/8562517-how-do-i-report-someone
In addition, discussions of cheating, potential cheating, or cheat detection are not allowed in the general forums.
this guy was definitely cheating
[removed -- MS]
he hasn't lost a game on his account and his account is 3 hours old