The auto park system is totally unrelated to the service brakes. If the shop wants to replace parts in the auto park system I would find a different shop because they have no idea what they're doing. The auto park system, depending on the version, uses either the pwoer steering pump or it's own pump to release the brake. Spring tension applies the brake so when the system fails it fails in brake applied mode. Your's is disconnected so shouldn't even be a point of discussion.
Service brake pedal going to the floor, air in the system or a leak. Did the shop bleed the brakes or add brake fluid?