I had the same problem twice now. SANDISK replaced it twice now for free but lost everything. I never had to backup my data from sandisk, each one only lasted 3-4 weeks. Both 32gb were purchased from walmart. I have not tried the new ones they send yet. maybe they fixed it. Can only hope so. This is what they said.
Hi Rick,
This problem should not occur again in the Samsung Galaxy S3. The issue with your phone is a unique case and its unfortunate that it has occurred more than once.
We apologize for the inconvenience caused.