Here's what I was told by the host:
Hi Tom,
Unfortunately, the issue with nameservers changes is that they can take at maximum 48-72 hours to take effect. Typically, it takes 24 hours with most providers, but your previous nameserver provider, PairNIC, had a high TTL (Time to Live) value which it can take a long time for changes to take effect. It's doing the same on my own computer right now as well, and when I lookup the path of how it's trying to find your site off on my own computer, it's still actually contacting PairNIC. During the transition period, it may go in/out. If you want to speed that up, you can switch your DNS servers on your iPad/computer to point to Google's Public DNS servers: 8.8.4.4 and 8.8.8.8. They grab the latest IP information and you should then see your site.
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Unfortunately, I called the customer care person at pairnic a very bad word. I stand by what I said, but this may take a day or two for some of y all.