If you have a frost free Fridge/ freezer, the fridge compartment temperature is controlled by a damper and thermostat. Your damper could be a turn of a dial that should say Cooler/ Warmer or it is controlled by a Circuit Board.

PCB responds to temperature settings you request for the above 0 C ( Refrigerator compartment) and signals a motor to increase or decrease the volume of Freezer air allowed into your chiller compartment. A faulty fridge sensor or damper motor, gearing or a broken flap will be your issue.