power seat - driver side - spontaneously reclines while off

My car crushed my toddler who was in the back in a carseat! The power seat - driver side - spontaneously reclines on its own, after the engine is turned off, and driver steps out and closes the door. This happened three times now. The kids were screaming in terror, as the seat kept reclining into them, effectively crushing them, and would not auto-stop when my older daughter tried to push back on it, to protect the younger one. The motor kept trying to depress the seat, even after it made contact with the toddler. The only reason he came out with minimal injuries other than trauma, is that the seat is somewhat soft. It's a very powerless feeling, being outside the car, walking over to take them out, being unable to stop the seat. I tried (to no avail) to push the seat back with my strength. The only thing that works, which unfortunately does not put an immediate stop to it, is to walk back, get into the driver side, and press the button to raise it back into its normal position. I've tweeted about this issue to @MazdaUSA as well, with no response.