All the gears are in neutral and they said the transmission is bad

Hello, Over time, automatic transmissions wear out. If there is no friction in the transmission due to normal wear and tear, lack of maintenance, or excessive loads, the transmission will operate exactly how you described. The brick behind the tire tells me they do not believe the parking pawl, which locks the output shaft of the transmission in place, can hold the weight of the vehicle, or they think it is not engaging when shifted to park. If that is the case, mechanical failure of the output shaft (in some way) is likely the cause of failure. You will want to get an estimate for rebuild and replacement, and see which you feel is better suited for you budget/plans. If you feel there is something amiss about the diagnosis, consider getting another estimate.