HI.
Unplug the fridge, open the doors and let it defrost for another 24 hrs.
If after that the same problem will occur - replace the
damper assembly
Part number: WR09X10050 
Here are the breakdown diagrams and
Replacement parts for General Electric GSS25JFMCWW Refrigerator | AppliancePartsPros.com
Thank you. Post the results.
Simon.