Hotpoint RLA64 Fridge

Have had this fridge almost 2 years and in general its OK. However the veg boxes are obviously not made for using as the plastic has broken already. The main problem I am finding with the fridge is the build up of ice on the back even though the fridge is supposed to defrost itself. i am having to defrost it every month. The fridge is too cold (better than not being cold enough) and if I put items too close to the back of the fridge they freeze!