Bought it three weeks ago and the sleep tracker device sometimes works ... sometimes doesn't. Very disappointed as that's what I bought it for mainly. Tried everything (logging in and out, restarting, cleaning sensor....). Did you find a solution?
I have the same problem and have tried everything that you have. It Tracked sleep and did my sleep score 2 nights then nothing since. Do you know how to contact customer support ? Every time I try to it says I’m not eligible for that service. I’m paying for premium too and like you wanted the sleep data!
I actually clicked on help then followed the link to the online chat support. Long story short they had me remove the device from the app on my phone then re-add it, also did a couple reboots of the fitbit. Nothing happened at first. I did this a few times and after a couple of days it all came back and has been tracking sleep ever since.