Mine tends to do that but luckily I managed to hit a point where the thing is still too cold but not freezer cold. Dare not even blow on the knob now. But it is likely to be a thermostat issue; mine falls off the ice box these days.
I suppose it's down to cost. Might be worth checking if you can fix it. But I'm unfamiliar how easy that would be on your model. Can only suggest that you check the costs out.