Dunlop Original Cry Baby Wah Pedal Is Not Working Can Any One Help?

i got a orginal dunlop cry baby wah pedal and it isnt working, the first one i got a couple days ago didnt work so i took it back for an exchange at guitar center and when i got home with my new wah pedal it didnt work again so does any know whats happening? and yes i am going up and down with my foot on the pedal!