Model ED5SHAXML 12 SIDE BY SIDE 15 YEARS OLD

tHE FREEZER IT TOO COLD AND SAME WITH FRIDGE
setting is warmest for freezer and almost OFF for fridge settings.

Working on the 3 rd thermostat in 6 months.

First (original) started doing above.
Replaced with new one but almost no difference....but could maintain temperatures at lowest settings. However recently box would shut off and only go on after off and on switching of thermostat.
Replaced this one and back to same above situation

Is this just bad luck with thermostats or are all the replacements junk.

prices can vary from $10/12 to over $100 for thermostat.

What else could it be