I have a Liebherr CNES3866 fridge freezer with a persistent problem - ice builds up at the back, inside the channel which drains the condensation. The little hole does not usually get blocked, but as the ice builds up, it stops the condensation water going down the channel, and the water ends up flooding the drawers and the bottom of the fridge. After trying to remove the ice build up incorrectly over the years, we have made a couple of dents in the channel, which I am sure don't help the situation. I imagine this must be a serious fault, but I am reluctant to call someone in, only to be told that the fridge cannot be repaired. Any suggestions? Thank you.