Why device turns off when on the Wi-Fi mode?
When I go on Wi-Fi and pick one of the opitions, for example Facebook, screens goes black and camera turns off. Why is that?
Have you tried doing this with the charger connected to the camera (and switched on)?
If the camera stays on it may be that the battery is failing under load and therefore the camera shuts down.
Even rechargeable batteries have a life span.
Have you got a spare battery that you can try to see if the camera behaves the same?