Don't even dare click on the site in case it's infected! What are they selling? Can't you just change your security settings so they just show as spam and delete them en bloc? Or get a 12 year old IT whizz to send every one back to them x 1,000 so their systems crash a zillion times a day. Is that legal? Probably not lol!
It's is a horse sales site from what I can see, only browsed it briefly. I'd go on it if I wa you and use the contact us to ask to be removed from mailing list