You might look at the following. It is about disconnects but much of the information can assist with lad and slowness.
https://support.chess.com/customer/en/portal/articles/1444918-my-internet-connection-is-fine---why-am-i-getting-disconnects-
Also, I suggest disabling Flash for the site as it can cause issues.
The main issue is that most lag is caused by factors outside of the site's control.
For closing accounts: https://support.chess.com/customer/en/portal/articles/1444763-how-do-i-close-delete-my-account-
Hey there,
hope you all are doing well.
I just want to let you know that I have a lag issue on a regular basis on that site and is very very disappointed with that issue. My internet speed is fine, and connection is great but i alwasy have a problem while playing a chess. It happens any time of day and i dont understand why Its not possible to regulate it somehow...
I love playing a chess, especially bullet and blitz but almost always upset when its laggy. I'm really tired of that and cant get why the site managers and coordinators do nothing to improve the situation with lag.. I am sorry but I do consider to delete my account which I set up many many years ago..
Any comments and support on all this would be appreciated!
Thanks,
Kamran
PS: who knows how to delete an account on chess com?