Did both sides stop working at the same time, or did one side start to play up first and then followed by the other side as it could be the door actuator....there are two little motors inside the actuator which start to play up and therefore wont open / close the lock.
Had the same problem on my Daughters car, on the near side, would not open or close and on the drivers side it wont open but does close.
Fitted a second hand actuator this morning on the near side and that now works a treat

just need to find one for the drivers side now