This was posted on Reddit, and thought I'd share it here:
"Got wasted @ the Funimation party (sponsored by MS Movies & TV) during San Diego Comic-Con. When it ended, I walked off with a box of these Groove Music Pass cards (thinking I just grabbed 100+ yrs of free Groove MP). It was out there for everyone to take as much as they wanted & it was barely touched. I used 4 card codes on my Xbox app later when I got back to my hotel & it seemed like it was working. Woke up, checked the Groove app on my phone: Nothing!
Anyway, I'd hate to see them go to waste. There are 48 codes on each of these images. Each image is about 5MB:"