This game is rigged and its not about difficulty rescaling like they try to make it sound like. Obviously balls disappearing when not stuck between rocks, major glitches in Nian battle where sometimes you do not get upgrades dropped or your balls start moving unpredictable compered to stage levels. RNG should be the core of this game as they promote but it isn't some things are fixed against you. And my gut feeling tells me that's because you haven't paid or haven't paid enough.