Refrigerator will not cool. Refrierator is just over a year old. My son raised the temp control to

Question

Refrierator is just over a year old. My son raised the temp control to 70, now I cannot get the temperature to go back down. The freezer works fine. There is power, lights work, doors seal fine.the freezer works great but the refigerator won't go below 50. had the problem a month ago and tried unpluging it for 24 hrs. I also cleaned the coils. It worked fine for a while but the problem is back. Its a kenmore model 596