you say the fridge seems fine so i have to rule out any defrost or damper issues. Normally when a customer tells me there freezer is not frozen but the fridge seems ok, i automatically think sealed system related issue. either the compressor is not running, due to a bad compressor or starter kit, or you have a sealed system leak of the refrigerant. if you do have a bad compressor or a sealed system leak, start shopping for a new refrigerator, as its a MAJOR repair for either whenever you have to open up the hermetically sealed refrigeration system
on a refrigerator, and its definitely not something you can do yourself, in fact its illegal, unless you are EPA certified for refrigeration.