Citing technical issues, Whitcoulls abruptly and with no fanfare shut down the ebook section of their website last week, and they are maintaining that explanation in their official comment:
The reason our eBook catalogue is off line is due to genuine issues around technical problems with the feed. Customers are still able to purchase eBooks directly through the supplier website however. At this stage we have no further information that we can advise on this and have no further comments.
Whitcoulls has been Kobo's local retail partner ever since Kobo launched in late 2009, and the Whitcoulls website used to host the New Zealand branch of the Kobo ebook store.
Kobo has not responded to my queries, and neither party has explained what technical issues they are facing, so there is really little to add to the story at this point. It's worth noting, though, that the shutdown did not provoke any complaints on Twitter, MobileRead, or elsewhere. This raises the question as to whether Kobo and Whitcoulls have a large number of ebook customers in New Zealand.
Or perhaps they were not sufficiently bothered by the shutdown to make it worth complaining. Whitcoulls customers can after all access their ebooks via Kobo, so this is at best a minor inconvenience.