Refrigerator Not Cooling?

One day my refrigerator, not the freezer, had stopped cooling. The freezer would work sometimes and sometimes it didn't. So we replaced it with another refridgerator and a day or 2 goes by and we notice the refrigerator on that fridge stopped cooling also. The same thing happened to that fridge as it did to the first one. What could be the problem? Is it the refrigerator or the outlet?

By Monique