Make sure you are logged in, then go to “Edit vCard”, next click “Account management” and select “Delete everything”.
URLS:
http://whistle.im
https://whistle.im/browser#vcard
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.