If you have а WHM Reseller account, you can suspend а cPanel user from your account.
1. Login to your WHM Account.
2. Go to Account Functions >> Manage Account Suspension or type Manage Account in the search box and then the option will appear.
3. Under Select by Domain, choose the user you wish to suspend or, should you know only the username, select the user under Select by User from the Drop-down list.
4. If you want to add a suspension reason, type the reason in the text field or leave it as it is and then click the Suspend button.
The account will be suspended and it will display the suspension message. You can read it to verify if the account is suspended or not.