Defective contact sensor

I just bought a ring alarm kit with 5 pieces and bought 4 other contact sensor on the side. They are all 2nd generation. Our windows are a little too wide and its very tricky to place sensors on closed windows without indicating that they are open. We manage to place 3 of them and the fourth one was showing open regardless the way it was placed. We decided to open the 5th one and test it. It worked Just fine! I believe this sensor is defective and I would like a replacement. I have been trying to contact Ring with no luck. What should I do?