Why is My car not engaging any gear position neither is it deploying brakes? on 2005 Mercedes-Benz E320

I got my mechanic to change the brake pads, then this problem started. He keeps telling me its the SBC, and I need to replace it with a new one, and for months he is yet to get a new sbc with the appropriate vin number to match my car.

Asked by for the 2005 Mercedes-Benz E320