Hoover fridge/freezer, fridge too cold

I have a Hoover fridge / freezer frost free A class HFA27KS. The fridge compartment gets too cold, to the point where it is freezing the food inside. It also builds up a slight layer of ice on the inside at the back. I have defrosted the unit and tried it again but it is the same issue, too cold. I have obviously turned the dial down to 1, but the problem still is the same. If I turned the dial down to 0, the fridge does turn off. Help! Can it be fixed easily?