Huh. Figures.
I've once been on the other end of this situation: a similar geolocation service (looking up street and city for a given zip code) which we relied on, stopped working overnight. Upon investigating further, it turned out to have gone over to be a paid service. Fair enough. Except the data they used was publicly available (by law), Took a whole thirty minutes to import the data, write a simple service against it (zip-codes are one of the few things you can actually validate with a simple regex) and have it up again.
Luckily the impact for our users was minimal, but it was a good lesson never to trust a public service. Especially one we weren't paying for.
Speaking of which, didn't something similar to this happen almost [url=http://slashdot.org/story/06/04/07/130209/d-link-firmware-abuses-open-ntp-servers]a decade ago[/url] already?