Your freezer fan unit may be frozen behind the inside wall and therefore not circulating the cold air down.
Se if you can remove the screws and back wall to check the fan unit.
Not all modeles can be repaired this way
James, frost on the suction line indicates that at the location where the frost is present, the suction line piping is below the dew point temperature of the surrounding ambient air and at or below 32°F.That's it. It's normal, the amount of frost may vary depending on the amount of humidity.