Contact the UWM Dining and Food Services via their web form "Connect with Us" at https://uwm.edu/dining/options/#h-vending to report vending machine issues.  Please add in the building and location of the machine as specifically as possible to allow them to find the malfunctioning machine.  A good way of describing the location of the machine would be to include the room number of a classroom or office located near the vending machine.