Lock User Account plugin provides functionality to lock WordPress registered user accounts in very smart way.
It has very quick controls to manage user account.
Install and activate plugin, go to Users page, select users you want to lock/unlock and then select the action from Bulk Actions drop down.
It has feature to add custom lock message to show on login screen for locked account. You can add your custom locked account message by going Settings and then click on General, there you can enter the message in field has label as Locked User Message.
