Received unit and installed a fresh battery. Does not power on. Googled and came across the plethora of power issues folks have had with these where they work over USB only. Tried USB, and it powered up. Useless for me if it doesn't run off battery though, so into the junk drawer it goes. Sad, looked like a cool little badge.
Sorry to hear about your bad experience. As discussed, you must use a LIR2450 rechargeable coin cell with Badgy for it to work. Regular coin cells (CR2450, CR2032, etc.) are under voltage and not rechargeable.