my american style fridge freezer FRSU201AW?

Hi guys, my fridge freezer is not getting cool. Freezer is working perfectly. The fan is going round in the freezer i have took the back off in the freezer and was very tiny ice build up which i cleared, i have cleared the drain plug, i have took the back plate off by the compressor and cleared all the dust off the fan. however, non of this has made any difference to the fridge which is very warm. any help please