You can cancel your account under the My Account section.
Go to: Login » My Account (Top Right Corner)On the popup, please select the reason why you are cancelling the account, then click on I understand that by cancelling my master account, all other accounts associated with this account will be automatically removed.
If you log in and receive a message regarding the account being blocked, you should see the Cancel/Delete Account link on the left. You can cancel your account by clicking on this link.