https://support.chess.com/customer/en/portal/articles/1444879-fair-play-on-chess-com-what-you-need-to-know
Discussions of cheating, potential cheating or cheat detection are not allowed on the general forums. If you would like to have that discussion, join the following group.
https://www.chess.com/groups/home/cheating-forum
Player rated something like 1400 play a standard game as GMs against me and of course win, and when I observed his history games he was losing from 1300 players. This site is full of cheaters.