I'm confused by this.

If the mounting post has come unscrewed, then the whole player face should drop off. The only difference is that the mounting post will be stuck to the face rather than stuck to the player.

The only time I'd see this being a problem is if the thread on the mounting post was stripped and it was simply turning in place rather than being unscrewed. Or perhaps you just haven't pulled off the player's volume knob yet? You should do that if you haven't.