help! please Hoover fridge freezer HNMF 3906A type PF37?

The fridge has lost it's chill and dropped in temp! Freezer was fine, so I turned up the dial to setting 4 and still fridge was warm. Freezer started to frost up so put it to 3. Still no joy. It's been turned off for 2 days.
I had the same problem round the other way fridge was too cold!
Can any one tell me why this happens.
One last thing the super light never comes on, is this it the bulb or is there bigger issues?!? Thank you