how can i stop this?

My hca 394 fk pw alu keeps freezing everything in the fridge and freezer! yes, it's ok in the freezer and supper cold. However it keeps freezing everything in the fridge to the point where ice builds up there. I have switched it on and off, have defrosted it and turned down the cooling to low to no avail. Can anyone help please??? in anticipation, thanks!