Freezer is freezing, but frig is not cold at all.

I was wondering if any thoughts about my malfunctioning refrigerator. Yesterday, I noticed that my refrigerator was not cooling anymore. There was no air coming out from the vent. The funny thing is that my freezer works fine. I can feel the cold air circulating in the freezer, so I am not sure what the problem is. The air compressor seems to be making noise and working. Does anyone know what could be the problem. The temperature gage is set to the coldest setting.
Please help.

 

Either where the vent is is frozen over or your freezer vent fan (evaporator fan) is not blowing cold air out of the freezer compartment down into the refrigerator section.

One cause of this freeze over can be the defrost cycle is not working.

Or during the defrost cycle, the melt-water can't get out, and refreezes/blocks, due to the drain line that goes from where it defrosts down into the pan is blocked with slime (typical), and then because the defrost water can't get out of the freezer it refreezes there and blocks the vent and defrost drain cup area at the upper rear of the refrigerator compartment.