The only thing I can think to suggest would be to fill a bucket with hot water and close it up in the fridge for an hour or two, while it's still empty. If there is ice blocking the flow of air from the refrigerant motor, that should solve it.
If that doesn't help, you might have a burned out motor. That's not so simple to fix unfortunately.
If the weather where you live is below freezing you can always get a few of those travel coolers and pack up the food outside. Just make sure to put weights on the lids so neighbourhood critters can't get into the food.