Defective product - Trijicon Bright & Tough Night Sights for Beretta 92/96A 1 Pistol

The front sight stopped glowing six weeks after installation. There should be a way of knowing the remaining life of night sights when you buy them. They have a twelve years life from date of manufacture. If the set you get is 4 years past that date than you only get 8 years. I doubt the front sight was 12 years old when I bought, it just defective. Am in the process of returning to the manufacturer.