GE refrigerator will not get cold
Typically when the freezer works fine but the fridge part doesn't get cold it's because the fan that blows the cold air from the freezer into the fridge isn't working.

If you are comfortable taking apart and reassembling the covering inside at the back of the freezer:


Unplug the refrigerator and look at the fan.
Is it jammed?  Does it turn freely?
If it looks okay, plug the refrigerator in.
Does the fan run?
If so, are the vents leading to the fridge part blocked?


Replacing a broken fan is easy enough, but, as with most replacement parts, it can be expensive.

For illustrations, see the manuals for your specific model on the manufacturer's web site.

There are also many YouTube videos showing how to replace the fan (e.g. Whirlpool).