Upload & Sell: On
Sounds like you've tried a bunch of different approaches, but I did not read (hope I did not miss it) trying the card on a different reader on a different computer. You may luck out that way.
Best of luck to you, I've had a failure once and nothing I did got the card back, I did not send out for expensive data recovery either. Fortunately, the session was spread out on different cards (i'm not that smart, someone was looking out for me :-) ) and I got enough off the other cards. I now shoot with a camera with dual card slots with in camera backup for important sessions!