Sadly, I've seen such before and not only have I run into card issues but card formatting issues. Support is non-existent so I hope you will format the card again and try a supported file system (NTFS is out!)
I recently purchased a Samsung Galaxy S Showcase (SCH-S950C) with Straight Talk. I also put a SanDisk 32 GB memory card in the phone. After a few weeks, I started to get error messages all the time on the phone saying the card was damaged or blank, followed by messages saying that the card was being scanned by the phone. It seems to happen a lot when the screen shuts off in battery saver mode and I then hit the power button to get the screen to come up again.
I called Straight Talk, and they said it's the memory card. However, I put the memory card in both my laptop and another Android phone and didn't have any problems with it. I also contacted Samsung, who told me to call Straight Talk.
Can anyone here tell me what the problem might be and how to solve it, please?