Sorry to hear about your MMI problems! Before you take it in for diagnosis, you might want to try to do a car reboot from its deepest sleep state (when you turn off the car it actually turns off very slowly, and only to an extent dictated by all the car settings): 1) close all the windows; 2) stop the car, get out and lock all the doors using the Key Fob. Press the lock button twice within 5 seconds to turn off the Motion Sensors (Ferry Mode); charging ports should be closed; keep both key fobs far from the vehicle and don't attempt use the MyAudi app; wait at least 3 hours before starting up the car again.