16 month old GE Profile. 16 month old GE Profile refrigerator with bottom freezer can no longer

Question

16 month old GE Profile refrigerator with bottom freezer can no longer maintain freezer temp. With control set at zero degrees, freezer temp varies from twenty down to six degrees. Both sides of cabinet around freezer door are quite warm although the ambient temperature is neither hot nor especially humid. This refrigerator has functioned perfectly up until the past week.