Whirlpool refrigerator with top freezer either...

Question

the fridge is only three years old but the bottom will not maintain a
constant temp and the top (freezer) develops a shelf of ice on the
bottom, around the area that should drain off. please help do not
want to spend another 600 dollars for a new one. Once the ice
shelf is chipped off, it will work ok for a week or so. help in bago