2020 AUDI A8 Power Train Problems

8/23/2021-I was slowing down at a red light and getting ready to stop but the light turned green and so high pushed on the gas to go before I got to a full stop. The battery warning light came on so I turned around to go back home can you swap cars. My fiancé had to go to work that day and took the vehicle. On his way back going 60 mph on the highway, The power to the vehicle shut down and he was unable to do anything other than slow down and pull off to the side of the road. The vehicle was sent into the Audi dealership and they changed out the 48V battery in the trunk. They also ordered an alternator but did not install it because it start it back up. A couple weeks later (9/25/2021) the same thing happened at a stop sign as...