Hi,
I'm not very good with tech things, but the standard size SD card has a little switch thing on the side of it, to lock it, (don't know if the smaller ones have that on them or not), if it is in the lock position it dosen't seem to work correctly.
If that isn't the answer, I hope you get it sorted soon, as it is soooo annoying to think you might have lost the stuff that was on it.
Regards
Sue