I wrote a message back to them saying that I think they're routing their confirmation emails through a server that's either been blacklisted and is blocked by other servers' spam filters, or it's going through a server with an open port 25, which most other servers recognize as a spoofable server, and they block emails from it.
Whether or not they do anything about it -- like cancel the vote and start over in order to be fair and accurate -- is still up in the air. But right now, all we know is that a lot of votes are not being counted.