Go to support.chess.com and on the top right you will find "Contact". Press that and email staff.
How to Report Abusive and Vulgar Language

"He also accused me of doing something to him that I did not do". Let me guess. He called you a cheater.

I just looked at your home page. You need to block him. Go to "your account" click on "privacy"--the pad lock. scroll down, write his name in the box. He won't bother you again.
I am not a prude, but it bothers me when opponents curse me out after I have beaten them. Just now the user [please do not name & shame others in the public forums or reproduce offensive content] after I put him in a position where I would either mate or win his queen. It's just not appropriate. There should be some sanctions for behavior like this.
[Instead, please report such behaviour to the Support team via the link given above, which is also available via Help -> Report Abuse -> Contact and directly via https://support.chess.com/customer/portal/emails/new. If it was in Live Chess Chat, get a screen shot; if it was a user note or message, don't delete it - Support staff will do so once they have investigated and verified. Thanks, David - moderator]
[Yikes - sorry about that - I didn't understand all of the protocols here. Lesson learned. Chess1981]
I got repeated messages from a user and I want to report him. He sent repeated, vugar messages. He also accused me of doing something to him that I did not do. I would not disclose his messages here, but go to my account homepage to see. Please report or give suggestions. Thank You!