Best to do this at the ISP level. If your ISP has web-mail... go there and
see if you can set up a spam filter. Often you can block not just an
individual but an entire domain. I have one email address I use for
registrations etc. It used to get tons of spam. (15 or so a day so maybe not
tons) But after marking each one as "spam" I amazingly get very little in
that spam folder any longer. It's like my ISP scolded these spammers and
they felt guilty and changed their ways. Seems un-realistic but true for me.