Block their domain and call it a day. The only thing that comes out of there is relayed spam.
Discussion
after not using it since 2013, i decided to poke around a little bit, and see if i could find a few people i used to know.
i'm trying to put together a team to build a website, and figured it couldnt' hurt to poke around there.
adding a domain block in postfix would I assume, be easier than unsubscribing, if it doesn't actually stick. if it sticks, fine, otherwise I'll just have my email server drop their domain... as you mentioned. :-P
how are you?