I have the exact same problem! I am so disappointed with Fitbit. This will be the 5th one I have had. Started with the Charge, had to replace it three times. Upgraded to the Ionic, not even a year, it doesn’t work and I’m returning it for an exchange.
I have to send it back and wait. No Fitbit that I paid good money for.
I would rather have all the money and time I’ve spent back and bought an Apple Watch . At least then I could go to a local store to get it fixed, instead of sending across the country and waiting!
Don’t waste your money on these products.