When you say it's not working, what is or isn't happening? Is the screen black when you are in the camera app? Is your image not being transmitted at all for the video calling, but you can see it on your screen?
start camera app by pusing camera button on the side of the phone
camera app opens and by default to the rear facing camera and image is displayed
I hit the camera/person icon directly to the right of the zoom in button
the screen goes black and does not display an image
the zoom in/out buttons and video camera buttons can be pushed but nothing happens what they are selected.
selecting the camera/person icon to the right of the zoom button again changes the camera to the rear camera and all is working again.
Also of note is that when the front facing camera is activated and I push the physical camera button on the side of the phone to take a picture, the camera app closes and goes back to the main screen with all my live tiles - as if the app is crashing.