The same happened to me after four months. No amount of restarting/resetting works. I had good help from one of the forum administrators who gave me the contact details of customer support via twitter (you don't have to have a twitter account). It was the only way I obtained a response. As I had owned mine for more than 45 days I was only entitled to a half refund or a replacement, which turned out to be "refurbished" when it arrived. My advice is to return it and make a decision about whether you want a new one or your money back before the 45 days expires so you can get a different Fitbit.
I was copied into an email from someone else today who had received a 'refurbished' replacement.
