Hello, and thank you for using this service. I'll be helping you with your problem today.
This sounds like a common issue and it means that your unit is not longer defrosting in the freezer so the refrigerator is not able to steal air to cool down. You'll need to either unplug the unit for 24 hours or remove everything of the freezer and remove the floor inside the freezer (requires you to remove both the refrigerator and freezer door to take out the floor and expose the evaporator coils
where the frost is). Once all the frost is thawed out, the unit will start working again. To make sure the problem doesn't come back, you'll want to replace the defrost heater. GE's defrost heaters fail often because they are nothing more than a long glass light bulb. Order and replace the defrost heater at the bottom of all the frost and you should be good to go. Below is a link to the defrost heater you'll want to order and replace. It's located under all the frost almost directly in the middle.CLICK HERE
Now I did want to point out that there are a few other possibilities like the defrost control board or the defrost sensor, but these rarely fail on this model and there is no way to test the heater for certain to know if it's good or not. The reason is because that the heater is glass and can get water inside of it when it fails so it will show good continuity even when it's bad sometimes. That's why the best course of action is to replace the heater since it's by far the most common problem. Also, if you happen to remove the back panel and the coils aren't packed with frost, then that would mean the fan above the coils is likely not running which will generate the same symptoms. You'll need to order and replace the evaporator fan motor if this is the case or thaw the ice out that is blocking the fan from running.
Please remember to rate my service before you leave. If you have any other questions, please ask me – I’ll be happy to respond. You can continue asking follow-up questions until you have all the information you need even after rating my service. Thank you!