Did you write support? Did you contact them through the support panel?
Did you get the announcements about upcoming mail system migrations?
Are you using POP3, IMAP, webmail, or what? What client software are you using, and what is your ISP?
Perhaps you're using 'server.dreamhost.com' (ie 'dot.dreamhost.com') instead of 'mail.realitysearch.com' as your incoming mail server?
I would suggest contacting support (from an outside address, obviously) at support dreamhost com -- or through the web panel, and let them know that you're having problems.