Well, the fact that you've spent your coupons and put your hopes too high on getting Minato [Edo Tensei] is already your fault .. Not every player in this game have the same fate over this events .. One may get something for free, others may get it with minimal spending, others may get it with some numbers and the rest gets nothing no matter how much they spent .. If you are playing this game for months already which i believe it is, you should've know already that this kind of events are RNG based ..