Yep, same issues here. Thunderbolt Ex3 worked for 2 days and suddenly disappeared. The amount of hours spent trying to get it back are gone forever. The associated madness and frustration have run their course. The only us seller on ebay want's $12...
Apparently these cards have a high failure rate? I just got mine working an 2 days later it quit. I barely used it 3 times. Sad. I hear the gigabyte alpine ridge card can be used instead.