Refrigerator Doesn't Stay Cold

I just went through that with mine, and after calling and talking to a repairman who couldn't make it out to where we are located. He suggested checking the temperature controls. The freezer unit should never, ever be set more than 1/2 way point on the controls. If it is set higher then the fridge spends all the time trying to bring down the temp of the freezer, leaving no cold air for the fridge. He suggested raising the temp to at least the 1/2 way point or "warmer" to allow the fridge to cool down properly. Don't know if it will work for yours, but it saved us from having to buy a new fridge.