Two weeks I had my model Y serviced for shaking of the car and steering wheel. They deemed the cause of the shaking due to unalignment of the wheels and they claimed to have fixed the issue. After receiving the car for the week after it began to make a sound of something hitting every time I made a U turn or any time I turned the wheel. While driving 3/8 with my family in the car I made a U turn in a parking lot and heard the same loud sound of hitting. When I went to check two large approximately 3 inch bolts were on the ground but no nuts in sight and my control arm broke the bottom plate and was completely unattached from the car. Thankfully the bolts came off while in a parking lot and not 20 minutes prior when I was driving on a windy road. Within 24hours Tesla contacted me saying my car was ready for pickup without any explanation of why the bolts came off, No full inspection completed for other issues and no alignment of the tires. Under the Tesla mechanic notes they only reinstalled the bolts and tightened the front wheels and not the back. Upon further research online I have found numerous other people complaining of the same issue of the bolts for the control arm falling off on Model Y and 3 Teslas due to forgetting to weld the bolt nuts to the sub frame.