The pile can only contain a limited amount of cash before you need to “claim” it. That maximum number is written below the bar, next to the CLAIM button. Your crewmembers start to sleep when the pile is full and their work can no longer be used. Be sure to claim your cash otherwise you will miss out on generating more cash!
If you have more questions, please contact us through the game by going to our Menu > Settings > Support. We can help you quicker this way, because the game will allow us to view your account and better help you.