After two weeks in the garage, I finally got my car back last Monday. There was something wrong with the gearbox that the mechanic fixed (replaced parts), he changed the ignition coil and I also changed the battery as it was causing a problem as well. Today, out of the blue, the gear box won't change or shift into Reverse as I tried to park the car. It does go to neutral and shifts to first gear but when I try to put it in reverse, the system gives me a beeping sound. Also, the sounds I usually hear when I shift from neutral to first gear is not as loud as before. The mechanic told me that it might not be engaging, any ideas?