If you have a larger churn rate you probably have multiple user accounts that are not in use.
In order to check suspended accounts go to: WHM > List Suspended Accounts or
To suspend an account:
You can also add notes to the suspension so that you don’t have to guess why the account is suspended:
/scripts/suspendacct USERNAME 'Reason for suspension here'
To prevent resellers from unsuspending the account you can add 1 at the end:
/scripts/suspendacct USERNAME 'Reason for suspension here' 1
To unsuspend an account:
In order to terminate accounts: WHM > Terminate an Account
or you can use the following command to terminate an account:
/scripts/killacct <user> <y/n>
(y/n indicating whether to save the DNS records)