In order to cancel your account (or a specific package), log into https://portal.wush.net/. Under Support, click on "Submit a Support Ticket," and choose "Cancellations."
You will be asked to indicate when you would like your account to be canceled, and confirm whether you have backed up your data.

If you still need a backup, you may download it in the Administrator area at https://portal.wush.net/. If you have forgotten your password, please use the "Forgot your password?" link. If you do not receive an e-mail within a few minutes, please check your spam folder.

PayPal users: Please note that canceling your PayPal subscription does not automatically cancel your wush.net account.

Alternatively, on the main page (wush.net), click the Contact link and follow the Cancellations link.