Warning problems of the 2019 Toyota Avalon

On two occasions, 8 months apart, our car started braking on its own while driving in traffic. In both instances, the on-screen alerts indicated the lda and simultaneously the check engine light. Neither time were we trying to switch lanes. In fact, the first time we were on a one-way street. In both instances, we were able to cruise over to a parking space before the car completely stopped avoiding a rear-end collision. Once we got in the space, we turned the car off and back on but it would not go forward or backward. We sat for 30 minutes or so, started it up and was able to get it home. We took the car to the Toyota dealership the next day. We got a call from the dealership in a few days stating the mechanics drove the car but the issue did not occur so we had to go in to the dealer and sign an authorization to allow access to the car's computer. About a week went by before we received a call stating they were waiting for an engineer to come in and diagnose the problem. Two weeks later, we got another call informing us the engineer would be delayed in getting to the dealership and asked if we wanted to pick up the car. Obviously, driving a car that we no longer feel safe in was not an option so we informed them to keep it until the problem was addressed. Weeks went by and we were not contacted so we sent a letter to the corporate office of Toyota. A case was opened but two weeks passed before we heard anything. We reached out and spoke with a representative who said they would have the initial rep call us. We never heard back so reached out again in a week and spoke with yet another rep who said there are two case numbers and the case is in progress and also told us there was "some kind of dispute" but we needed to speak with the case manager who opened the case and they would have her call back. Here we are nearly 3 months later and there has been no resolution. We've not heard back from the dealer in over a month and the corporation in nearly 2 weeks.