In order to enable/disable email service for a particular email account from MailEnable interface one needs to follow below mentioned steps:
1) Login into MailEnable server.
2) Open MailEnable Professional Admin.
3) Go to MailEnable -> MailEnable Management -> Messaging Center -> Post Offices.
4) Go to the domain for which one needs to enable/disable email account.
5) Double Click on that domain name.
6) Go to mailboxes.
7) Right click on email account for which one needs to enable/disable email service.
8) Click on properties.
9) Go to General Tab.
10) Check/uncheck the checkbox against the Mailbox is Disabled.
11) Click on Apply and OK.