You might've been able to swap it back for a new one if you contacted the team or something :[
I've had mine since the thing first came out, the black one, that came in folded paper. That's more than a year at the very least. It's been dropped, had the microSD cards fly out, the card was once inserted and taken out more than 50 times in an hour (damn Daigasso! Band Brothers DX...), swapped firmwares, experimented with, amongst other things.
The card will work for you. It's a great purchase, easy to use, menus aren't hard to modify to your liking (everyone always says they are >.>), and seem to be rather cheap for their product. I say enjoy their things while they're still at it.