no storage manufacturer warrants the data on the product. only the product it self is covered by the warranty. this goes for any storage product from HDD to tape drives and everything in between.
what you have experienced is actually pretty rare. having the same issue occur with 2 different cards back to back is not something that happens often. sandisk cards are among the best quality products that can be purchased.
that being said it seems there may be something else in the mix that may be causing the issue. the fact that the card works in the camera and the data can be recovered successfully seems to point to the card working ok. the actual data was not damaged or corrupted. if it was data recovery would only recover corrupted data. what kind of card reader are you using? the card reader may be the issue and could be not reading the card correctly. you can test by using the camera as a card reader. if images can be captured and viewed on the camera connect the camera to the computer and use it as the reader. if the images appear normally on the computer when using the camera as a reader your card reader may be causing the issue.
