Sorry about the inconvenience. We will definitely get it resolved as fast as possible.
Can you follow the steps below to test the light?
1) Remove the pocket clip if it is installed (important step).
2) Unscrew the head from the body tube. Unscrew the tail cap from the body tube.
3) Use a piece of clean cloth to wipe the threads on both ends of the light tube.
4) Install the head on the body tube and fully tighten it.
5) Install the battery with the button top towards the front of the light.
6) Install the tail cap and fully tightened. Most issues are caused by looseness in either head or tail cap.
7) Press and hold down the switch button while pointing the light to your other palm.
Does the light work now?