How to get rid of a site that has attached to my address book?

a site http://;kaqabise.t35.com/ and tordirect.net/contacts has attached itself to my contact list and is sending out e-mails to these people and companys this is being done when I am not home or even when I am off my computer. I have gone to their site and requested that they stop 3 times now and they will not I have had to delete my address book to stop these people from sending them these e-mails in the subject line they put NO Subject. How do I get ride of this parisite?? also when a few friends opened up the e-mail it asked them to go to and sign up for YAHOO? whats up with that?