Freezer coils at back get

Question

Freezer coils at back get frozen thru to plate at back. Cold air does not get thru to fridge sufficiently. Now we have freezer set between 0 and 1 and fridge at 6. Freezer is extremely cold - fridge normal. What is the problem? Pls give us some ideas as to what could be causing this. We are on the point of buying another and this one is not that old!Jean Welsh