Hina Fes is Hello! Project's annual Hinamatsuri concert that spans over 2 days. This year has 2 very popular H!P acts returning as guests, after they've been gone for many years so people are scrambling for tickets.
From what I've been told, the tickets that are being resold are tickets that people won from the fanclub lottery. The general public tickets haven't been put on sale yet, so I imagine the prices will go down eventually. I get why some people are upset, since the scalpers are taking advantage of the lottery, but it's not like all the tickets are gone either.