Check the thermostat to make sure it hasn’t been turned way down by mistake.
Be sure the vents on the back of the freezer compartment aren’t blocked by boxes of ice cream or frozen food packages-the vents have to be clear for cold air to circulate.
Vacuum the coils under or behind the fridge. Clogged coils can cause poor cooling
Clean the seals around the refrigerator doors to keep cool air from escaping