how can I fix my Candy CPC290FFK?

On return from holiday 7days ago,we discovered that our Candy CPC 290FFK Fridge Freezer was not working properly. When the fridge door was opened the light failed to come on and a bottle of milk which had been placed in the fridge the previous day had frozen solid. Replacement of the light bulb failed to make any difference, i.e., the light still did not work and items placed in the fridge section since then have also frozen. The freezer section of the appliance seems to be working satisfactorily. We also notice that the backwall of the fridge has an increasing thickness of ice. Can you please offer any advice as to how the problem can be solved.