Please go to: http://mailman.xmission.com/cgi-bin/mailman/options/dynix_l or http://mailman.xmission.com/cgi-bin/mailman/options/horizon-l http://mailman.xmission.com/cgi-bin/mailman/options/Saas_l
at the end of the URL add your email address. It will take you to the mailing list membership configuration for your account.
You will be able to make the changes necessary or request your mailman passwords to be sent to you.