electrolux enb32000w

the above f/f is frost free, the thermostat is set to 6, the fridge gets cold at this but not lower. the wet back dosnt appear to be freezing droplets all the way down only about 1/3. the freezer compartnebt is cold enough, there is ice at the top of the freezer in the middle roof part, there is also a small puddle of ice near the rear back plate inside the freezer, the compressor does not seem over hot but customer it has made a funny noise in the past, can u pls tell me why the fridge is not cooling at 3 and the wte plate does not ice up correctly, appliance is about 15 months old.
thanks