adwsystems:
If you are checking continuity (ohms) from COM to NO then it should be open when not pressed and closed when pressed. If this is not the case, then the switch is kaput. (You should also check COM to NC with the opposite actions on the switch)
Not sure if what I'm seeing is correct, but it looks like the NC and NO terminals on the microswitch are wired together. Running a probe from no/nc and a probe to com shows there is continuity, however there is a spike in resistance when pressing the button, and when releasing the button on the microswitch. Wonder if this could be what the regular vending machine controller is looking for to turn it off?