I guess you're trying to unsubscribe from ubuntu-gr list: visit https://lists.ubuntu.com/mailman/listinfo/ubuntu-gr and check at the end of the page where it reads:
"To unsubscribe from Ubuntu-gr, get a password reminder, or change your subscription options enter your subscription email address:" -- Ubuntu-gr mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-gr
