You'll need to either:

1) Contact the Faculty Student Association (FSA).  They oversee the vending machines and can help you recover your money.  The FSA office is located behind the Campus Bookstore. You can also walk through the Bookstore to get to our offices. The FSA is open Monday through Friday 9:00 am to 5:00 pm. Summer Hours are 8:30 am to 5:00 pm Monday through Thursday. Friday summer hours are 9:00 am through 12:00 noon.  You can contact them via the following page

2) If the FSA is closed you can report the machine, building location and the amount you lost to the vending machine company. The company will reimburse the student via a check in the mail to their mailing address.The number is 914-347-3910