If you do not receive coins after an absence it means you assign your staff for completing orders from the car or for making the phone order. In this case, your staff is busy with completing these orders, they don't serve customers and don't earn coins.

Please, kindly note that if you assign 2 baristas for completing orders, waiters won't bring profit as well because there are no available baristas for preparing the dishes.

Make sure there is enough furniture to serve customers. You should have bar counters for a barista, and tables for waiters.

Do not forget to exit the game correctly. When exiting, you need to press the Back button on your device, a window should pop up with the question: "Do you want to leave the current game?" Then you can check the task manager, the game should be deleted from there.

By following these simple rules, the cafe will always generate the highest possible profit.