http://wikimania2007.wikimedia.org/wiki/Cancellation_Policy
Section : If you pre-registered with accomodation
"Cancellations filed before Sunday 20th May 2007 Taipei, UTC+8 will be taken
into account and partially refunded. However, if you submit it later than
20th July, 2007 , there will be no refund."
Ah, that is the problem, me too.
Is it 20 May or 20 July?
As I see the page now, May is correct.
--OTA Takashi