Disabling a client account prevents that client from being able to log in to view and manage their form submissions. When clients try to log in with a disabled account, they will receive a message on the login screen informing them that their account has been disabled. Note: disabling an account does not prevent any form submissions being stored for any of the user's forms. To prevent this, you must disable the form itself.
To disable an account, click on the Clients link in the leftmost navigation column, and click the appropriate EDIT link. On the main tab, change the value of the Status setting to "pending".