I have numerous problems with my charge 3. I purchased it July last year but over the last few months it has developed problems. Lines on watch face, screen won't swipe, no heart rate being recorded, stair climbs being recorded when walking on the flat, random changes on watch face. I emailed directly to Fitbit but have had no response. I have tried the fixes suggested, restarting the watch, changing the clock face etc etc but nothing works.
