Franklin Sensors ProSensor M50 Professional Stud Finder

I bought the Franklin Sensors ProSensor M50 from Amazon. A friend recommended this brand and proclaimed it the best for the price. I opened the battery compartment door of a brand new product just out of the package and - SNAP! The thin, flimsy piece of plastic designed to hold the door shut broke off. The battery compartment will not stay shut now. I did test out the sensor to see how it worked, in case I wanted to get a replacement. The sensor does not work properly. It has 5 lights on it to identify where the stud is located. The sensor would not light up any lights going across a stud from left to right, but would light up if being moved from right to left on the wall over the same stud. I also noticed that I would have the first 3 lights on (far outside, next, and middle) showing a stud. Then, after moving the sensor maybe 1/4" suddenly only 1 light was on. I don't know how a 1.5" wide stud could almost vanish in 1/4" of movement like that. The lights were dancing around a lot like this. It was bizarre and unusable. I had areas in my house where items were secured to studs with the help of a friend and his stud finder previously, so I know where the stud is located. This sensor was a bad guess and not an accurate measurement. Zero confidence this Franklin Sensors product knows what a stud is. I called a phone number for Franklin Sensors on a card inside of the package with the sensor. No one answered and no one returned the call after a few days before writing this review. I tried to give the company a chance and see how the customer service would be. But, no one even attempted to defend the garbage product I had bought. Sending this back to Amazon, and probably looking at another brand (or at a minimum another model without these flaws).