Alright, so you decide to, one day, go outside and mine for diamond. (Yus, Minecraft.) You manage to find some diamond ore, so you mine it for a gem, hitting it with your Iron pick until the gem pops out of the small cube. Moving to pick it up, someone pushes you out of the way and takes it from you! That person is the person above you. What are you gonna do about that?
The non-prologue version:
The person above you has the diamond. Use any means necessary to get it from them.
Fun violence is fun.