Expandable storage such as SD cards are great. They can make your phone or camera a much larger and more versatile beast. But when a card corrupts you can lose a lot.
Here's what to do if your SD card has stopped working. First of all, don't format the disk if you want to retain any of the photos on it. And unless you have a lot of valuable data that you absolutely need to get back, we'd caution against employing a third-party data-recovery company. At least not before you have tried the following.
How To Recover Files From Corrupt SD Card.