Use their webform and request deletion. Termination of your account will only be possible if you have no outstanding orders/actions. According to their PP all your data will truly be erased. Now that is clear, the way we like it.
Please note that AccountKiller.com is not associated with the business listed on this page. AccountKiller provides easy-to-understand instructions and guides on how to cancel charges and relationships from the list of businesses on our site, we have no affiliation with these businesses.