Not to be rude, but you could see an image in your RF patch right? You didn't have your finger over the RF window or something simple like that (a mistake I've made a few times)?
If it's not that, the camera RF cam may have gotten pinched or stuck back all the way and become unable to move. With the lens off, you should be able to push the little roller & arm back, and have it spring forward as you release pressure. It should move back with some resistance, then spring forward freely. Don't force it though, because this is a precision part of the RF mechanism. If the cam sticks, it may need to be lubed or adjusted.