Images and videos not readable from SD first time here and I'm in sort of despair!

I recently purchased a 32GB (class 10) memory card for my Samsung Galaxy S2. All went fine, the card was recognized, I could write and read from it, both, on the computer and the phone so I set it as the default storage for my camera.
The problems start here.
Last week, after shooting some videos, I wanted to check them at home but realized that the videos and some of the photos are not shown, the videos cannot be played by the phone or dropbox player or VLC on computer, jpg's are corrupted too.

I tried formatting the card, but the problem still persists. I'm pretty stumped right now and don't have any ideas on how to fix this.

Any help appreciated, thanks!
This might be some compatibility issue -- despite the fact that it seemed to work fine initially.

It's not the first time I read such in connection with a class-10 card. I'd recommend to get yourself a class-6 (good enough and fast enough -- only in rare cases you would really note any difference), maybe preferably from a different brand than the current class-10, and give that a try.

Chances are very good your trouble will disappear this way.