AllPoint ATM Money taken not given Indianapolis,Indiana

 I went to an AllPoints Atm to withdraw $40 from a location at a CVS as I finished the transaction the screen flashed red and gave me no money. I waited 5minutes and the screen went to the main screen again no money, about 3minutes later I received a text message from Skylight Financial saying $40 had been withdrawn but again I received no money. I called Skylight that proceeded to tell me to call the arm company posted on the atm and if I do not receive a response from them to call back and within 10days they will provisionally credit my account. They also proceeded to tell me this happens frequently when the arm runs out of money. I don't understand how this can be ethically correct to do to someone the machine knows it's out of money but it takes your money anyways this should be illegal