Unit failed to work - Streamlight ProTac HL X 1000 Lumen Flashlight

I bought 2 units. Both worked out of the box and produce excellent light. However after several uses 1 light doesn't work! I left the unit in the truck several days during sub zero temps and the unit failed to turn on. I swapped batteries, switch and lens between units and it still doesn't work. Very disappointing for a high end flashlight. Great light when it works however can't recommend this due to quality issues. Like the unit that works and hoping it stays working.