Ok the likely problem here is that moist air got onto the evaporator and condensed building frost up on the evaporator (located in the freezer), To clear the problem you will need to either unplug the unit for 24 hours in order to let the frost on the evaporator melt.
If you have no where to put the food remove the drawer, then remove the drawer, next remove the ice maker
from the freezer, next remove the panel on the inside of the freezer rear, once out you will see the evaporator (looks like the radiator on a car) there will be excessive frost on the evaporator, melt this with a hairdryer set on low heat. Once melted button the unit up.
Although the fridge is not cooling the air that is blown into the fridge comes from the freezer, if frost covers the evaporator then cold air cant pass over the evaporator and the heat exchange cant happen causing the fridge to warm.
Always remember to unplug the unit when cleaning it.
I would like to earn your highest rating, if you are not totally satisfied with my answer please hit the continue button.
If I have answered your questions to your satisfaction please feel free to come back at any time after rating me "Excellent service" for additional questions you may have at no further charge :)
Sometimes I will have to give bad news, Please try to find it in yourself to rate me for the service not the bad news.