Check the inside rear wall cover in the freezer for a frost buildup, you can remove this cover to view the evaporator coil to see if it's iced up.. If so then you're having defrost issues... Locate the defrost timer, usually in the fridge compartment but not listing a model number makes it anybody's guess.. There's a knob on the timer that turns CW to a noticeable click which is the defrost cycle, make note of the time and inspect defrost heater under evaporator coil in the freezer for any signs of heating up... If the timer doesn't bring the compressor back on after 35 minutes or less then that would indicate a defective timer... Look for a part number on the timer and input it into APPros number search... If the heater doesn't heat up then you may have a defective heater or defrost end thermostat... Try to find a model number for this fridge... Use a hair dryer to remove the ice buildup...
Good luck, kooler