I called both Mosaic and Amex last night. Amex confirmed my card was cancelled on January 8.
Per Mosaic, my TrueBlue account still shows me as an active cardmember.
Per Amex, they have no responsibility to report account closings to JetBlue. Yet JetBlue claims they cannot update TrueBlue accounts unless Amex tells them the account is closed. Something is off here.
I've seen other cancelled cardmembers complaining via twitter over the last day as well about the new card notices.
Maybe it's time to take this to Mr. Hayes.