Frozen Neff Dishwasher?

My dishwasher stopped working and started bleeping. When I opened the door a tap symbol was illuminated. When I checked the impellor on the pump it was frozen solid. There was also ice on the inside of the machine. There is an airbrick in the wall behind the appliance and with the -18 temperatures I guess it has been ice blasted. I have poured kettles full of boiling water in it and freed off the impeller. After a while of stop starting it began to work. However it isn't emtying properly and even with the door open it still makes a noise as if it is trying to empty but the water is just swirling around in the bottom. Do you think it is still partially frozen or is it broken?