This can be a common issue in many cameras. Buttons tend to worn due to bouncing the key so much. Also, the buttons can become sticky due to residue underneath the keys. Make sure you do not store the camera in particularly dusty, humid, or high temperature conditions because this can have adverse effects on the electrical contacts of the button switches. You can try to reset the camera to the factory reset, putting everything back to the way it was the day you took the camera out of the box. If that fails, you can send your camera back to the manufacturer to get the button replaced and to make sure there is no further damage to the keys. Hope this helps!