Side by Side refrigerator/freezer

Freezer temperature swings from -10 to 30 degrees. Refrigerator side swings from 36 to 42 degrees. Originally noticed swing because ice cubes were melting then refreezing; ice cream was soft then would refreeze. Replaced relay kit, defrost timer and cold control in freezer. Problem still exists. Coils were cleaned. Technicians are stumped. Help!