Removal from Conlang list

I am with Celticonlang and verious other lists and they're becoming
too much to handle so I'm trying to whittle them down - including
present list - but am having trouble with Conlang. I through we were
on eGroups but was then told we were on "William Brown" but help and
unsubscribe commands to their server do not work. Does anyone know
what the magic formula is?