You can properly cancel your account from the client area:
Click "Services" and then click "My Services"
Find the hosting plan you want to cancel and click the "Active" button.
From the "Actions" menu on the left, click "Request Cancellation".
You will then be able to choose when to cancel the account.
Your account will then be automatically cancelled and terminated (data is removed from our servers) for you at the time you have chosen, so be sure on your decision to cancel.
For domain name renewals, if you do not want to renew the domain name, please disable auto-renew for the domain name in our client area as well.