Search for Photorec to recover your pictures. It is open source and free to use.
After that low level format your card in the camera. If you still get problems buy another card
DCS 3c, DCS 520, D30, D60, 1Ds, 300D, 30D, 1000D IR, 7D, 6D, 6D, M5
15-45/3.5-6.3 IS, 16-35/4 IS, 22/2, 24/1.4 II, 24-105/4 IS, 50/1.4, 50/1.2, 85/1.8, 85/1.4 IS, 100/2.8, 70-200/2.8 IS II, 300/2.8 IS