If the fridge is still working and defrosting it sounds like a build up of ice behind the freezer panel is causing the problem. Try turning the fridge off overnight so that the fridge/freezer thoroughly defrosts. Place a few towels round the drip tray at the back of the fridge first.(food is normally OK for about 12 hours). When you turn it back on the freezer should hopefully start working properly again. If not the defrost timer switch may need replacing.
Bob, July 2008