Is all lost?

“No. SanDisk does not offer or provide recovery services. They do however, back up their products (in this case, memory cards) with a generous warranty period and replace any that fail within that time.”

Seems like Kodak’s warranty on film. If the important photos you took are lost due to defective film, Kodak will give you a new roll of film. 

Having cameras with two card slots which can be set to have every image taken written to both cards seems like a great thing. It wouldn’t cost that much extra to add a second card slot when designing a camera.