2023 Audi A5 BACK OVER PREVENTION,FORWARD COLLISION AVOIDANCE

Over the course of 3 days about 6 weeks ago, my new leased vehicle abruptly slammed on the brakes 3 separate times for NO reason whatsoever. The first time the vehicle was in drive mode and abruptly slammed on the brakes from a speed of 10-15 mph in the middle of a left hand turn. The second time the vehicle was in reverse and slammed on the brakes from a speed of 5-10 mph. In neither case was there any reason for the suddenly abrupt and startling braking to a complete stop. The third time the vehicle was in park and idling in an empty parking lot and AGAIN the pre-sense system abruptly alerted and although braking could not be applied (because the car was in park), the seat belt system abruptly slammed me against the seat. I brought the car into Audi, who evaluated the vehicle and found NOTHING WRONG WITH IT. They said, "maybe a paper bag flew near the sensor or the sensor was dirty." I expressed that I did not feel safe driving the vehicle and they said I have to take the vehicle back. I requested that they disable the pre-sense system and they reported that they were not permitted to. I reported the incident to Audi corporate who agreed with the dealer. I feel the vehicle is unsafe and because of past performance, could suddenly and abruptly slam on the brakes causing a major car accident. Please assist if you can.