3 Answers

Before you spend any money, do what we did.  Occasionally the unit inside the compressor becomes totally frozen either too much stuff in the refrigerator and/or freezer or insufficient circulation.  When this happens, the whole unit "freezes up" and shuts down the cooler entirely.  When this happens, you'd need to "thaw" the entire compressor unit.   Unplug the fridge, pull it away from the wall, and, with a hair dryer, "thaw" inside of the freezer (open the freezer and it's in the far back of the unit).  When you feel it's sufficiently thawed, plug the unit back in. 

Don't forget to remove all perishables from the fridge prior to thawing of your freezer.

Compressor is bad or freon needs a recharge. A new one might be cheaper.

time for a new one. New ones these days are extremely efficient.