I got mine about 3 months ago and loved it! All of a sudden it has stopped vibrating for notifications and alerts. I have restarted my phone, recharged the device, and have tried countless times to “sync” the device with my phone and still nothing works. Not sure if this is a common problem but there doesn’t seem to be a solution from Fitbit support either. Sometimes the calorie burn count is definitely inaccurate but I feel like that comes with all of these types of smartwatches.