This is a visual error that is caused by a loss of internet connection. If you watch carefully when you return to the game, you will notice that your cash/shields/spins have increased--the spins were generating prizes while the game was attempting to make a connection with the server. You may see a decrease in the amount of spins you have left, but they were used to earn you rewards from the wheel.
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.