I defrosted my fridge freezer yesterday for a few hours. All the ice was cleared out. When I turned it back on the freezer is working perfectly but the fridge isn't working. The light goes on and there is a humming as if it is working but it's only at about room temp inside the fridge despite putting it at the coolest setting. It was working grand before I defrosted it! Any ideas what might be the problem with this or do I need to buy a new fridge freezer? Thanks.