Are you sure the e-mail was sent through Jazz2Online or the JCF? E-mails from Jazz2Online would have an @jazz2online.com address. Other e-mails were probably not sent through the site.

Your e-mail address is hidden from other users by default. Users can still send you an e-mail via a form, but then they can't see your e-mail address. You can disable that too, like I described in my previous reply.