If you use WHMCS or Blesta, this happens automatically for unpaid or canceled services. Here's how to do it by hand.
Suspend or unsuspend
- In WHM, go to Account Functions → Manage Account Suspension.
- Pick the account, add a reason if you like (only you see it), and click Suspend.
- To bring it back, open the same page and click Unsuspend.
A suspended account keeps all its files, email and databases. The website shows a suspended page and the client can't log in to cPanel.
Terminate
- In WHM, go to Account Functions → Terminate Accounts.
- Pick the account and confirm.
Terminating deletes everything in the account: files, email and databases. If you might need anything later, download a backup first with JetBackup in that account's cPanel.