You can simply redirect traffic from their domain to an empty page.
It can be done in .htaccess
Something like this (not sure if it's exactly correct)
RewriteEngine on
RewriteCond %{HTTP_REFERER} ^http(s)?://(www\.)?sublimedirectory.com.*$ [NC,OR]
RewriteRule .*
http://adomainame.com/empty.html [R,L]