There is an amazing lack of information and feedback on both the Kolor and Panobook websites.
This has been the case for pretty much every Panobook contest. The winners are typically announced sometime between the end of May and the middle of July. The only other place that I know of to ask questions about the contest is on the Panobook Facebook page. Kolor posted there on April 30 that the results would be announced "in a few weeks." I have been slowly conditioned the last few years to not get my hopes up that the contest winners will be chosen in any timely fashion.
I also noticed the discrepancy between the number of entries they said they got, and the number visible on the site. I'm not sure why your entries seem to have fallen off. I sincerely hope that the extra ~400 entries are still considered in the contest!
Trying to wait patiently,