They just shut off DNS to those sites and others registered to Cassingham, and even to a site that listed him only at the technical contact. They didn't bother to email any concerned parties about that, either.
It took several hair-tearing hours for Cassingham to figure out why no one could reach his sites and all his email addresses were down — why his livelihood had suddenly vanished, in other words. After he learned that Enom had cut him off, it took nearly 24 hours more to get his DNS restored.
Enom never responded to Cassingham's desperate communications with a single word of acknowledgement, explanation, apology, or advice.
The phone number was changed by Cassingham himself as he updated obsolete registry information. Like most sane people, he was loathe to put his office phone number in the registry for every con artist and crank to harvest, so he entered a placeholder number until he could get a voicemail flak-catcher. All of his DNS records contain a valid email address that auto-responds to incoming messages with Cassingham's full contact info, including a valid voice phone number.
OK, so Cassingham made a hasty mistake by not waiting until he had a valid voicemail number. More likely, his real mistake was using such an obviously bogus placeholder as "0000000000". Whois records are rife with plausible-looking contact info that doesn't work. Indeed, Cassingham's income would not have been interrupted and his heart slammed into fibrillation had he simply left in place the contact info that was obsolete since he moved in 2003.
But Enom made a bigger mistake by biting the hand that feeds it, without so much as a warning snarl.
Any domain registrar can do likewise to anyone at any time. I wonder how many have.
How do Slashdot readers manage their DNS records for privacy and security? If you manage a registry, what do you do when you discover possibly bogus contact info? What would you do if your registrar pulled a stunt like Enom's?