2021 Toyota Highlander brakes problems

Vehicle had a very loud high pitch whining noise the rapid accelerated I was braking and brakes were not working vehicle screen was flashing Vehicle Malfunction. yes vehicle is available. I could not stop the vehicle I struck three signs and a lady fell down as i was approaching the the building very fast, hit a wrought iron black fence and it fell on a park vehicle and then i hit a park vehicle and it stop i threw it in park. i am not sure.

We are experiencing pcs is not working, we were driving on freeway when cars stopped suddenly and not even displaying any warning signal of 'brake' on that moment, we were so close to impact a trailer, second time similar situation the next day after the first appt at service where they stated that pcs was working properly , cars stopped suddenly and not even with the warning timing set up in to the 'early time', warning us to use the brake.