So I was gonna auction 1 redstone block, it was now my turn, and suddenly, poof. The systym on skyblock crashed, i had to rejoin and my redstone block was gone, and it didnt auction (didnt get money)

 

well, sadly things like this often happen when a server crashes, or entity clearing at a moment you least wanted it.
the staff can't refund the items if you don't actually have a screenshot of holding the item