All the buttons and switches related to the seat command the “ECU” or seat controller box and that in turn commands the relays for the motors. If the seats don’t move and the mechanics are not blocked and the buttons and switches work and the internal microswitches in the seat work (there are a couple), then it must be the seat controller box at fault. With the seat out of the car the seat just needs power and can be fully tested, it can be considered a stand alone system.
You say the seats move back automatically. This is not how it is supposed to work. The box just remembers the position the seat came from when automatically moving the seat forward after moving the backrest forward. When you move the backrest back into normal position you must press down the handle on the backrest for the seat to slide back into the original horizontal position. It is semi-automatic, so automatic moving forward, manual moving backwards to the “remembered” position.