My Mira Event power shower does not pass or pump cold water?

During a recent water cut the header tank to my shower ran dry while in use. After the water supply was reinstated and the tank refilled the dhower no longer pumps cold water. the motor is working but the only water that comes through is scalding hot. I wonder if the loss of water has damaged the pump an d if so is it repairable. This model is around three years old.
Thanks
Andrew Herbert