That's fucking hilarious man, really. Like that sounds like an experience, I would have been upset that I didn't see them but that still sounds kinda fun in its own way.
Though they havent had a word since they may have their reasons or something could have happened, to just get up and destroy their equipment and just start hating them for a disappearance, especially after the fact that you will get a refund, its fucking stupid and kinda self-entitled. Sure you may have wasted your time a bit but I doubt you'd do anything better with your life and regardless that just seems like an interesting, even if at the time it was frustrating, time.
TL;DR Get over it, not that big of a deal Death Grips does crazy shit all the time, thats a part of what makes them so great to follow. Maybe they were partying with Robert Pattinson. Still kinda wanna go to the New York show if they dont cancel it by then.