1) Probably dust on the focussing screen.
Take it out, and wipe it clean. (Dry. If must be, breath on it, then wipe).

2) After frame 12, the camera should wind and transport the film using the wind knob/crank on the camera.
After that, the crank on the magazine is used to wind the film entirely on the take up spool.

If neither works, there is a problem that needs to be solved. Ask KEH about footing the bill, or return the camera for a better one.