You may remove your website at our dashboard. When you log in, you will be able to find a trashcan button around the blocking/alerts box. If you click on it, then your website will go into bypass mode. Within a week, the website will be deleted from our systems automatically. In other words, the website will not be deleted immediately. Please do not forget to restore your DNS records to your original ones.
If you want to delete it immediately, then please contact us via live chat or firstname.lastname@example.org.