Front Seat Power Adjust problems of the 2007 Infiniti M45

The driver side front seat mechanisim has failed in my vehicle. This vehicle is equiped with six-way power adjustable seats. As I was driving the vehicle, the seat suddenly drop to the lowest position on the floor and will no longer raise or lower. As well, the seat now seats not to be properly anchored to the floor of the car. The right side of the seat belt is attached to the bottom of the seat rail and when I stop or put any tension on the seatbelt, I can feel the seat moving about. I am afraid to allow my son or my wifde to drive this vehicle as it seems that the seat will not stay anchored to the floor in the event of an accident.