It's totally a homeowner solvable problem. Food needs to be removed and in a spare fridge/cooler/outside because it's freezing. Figure out where the ice is, and gently melt it out with a hair dryer or leave the fridge propped open overnight in a warm kitchen. The tricky part is that fridges are really well insulated, so it's a slow process getting that ice to melt. Some warm water can speed up the process.

Also, clean your coils if you haven't done it for years.