 One thing to check
I had the same problem on a Kenmore, the compressor was running fine, defrosting correctly, turns out it was the evaporator fan motor not working. On the unit I worked on, it was behind the sheetmetal at the back of the freezer side and circulates air up and around the freezer. If left alone, the cold air falls and the hot air rises resulting in cold down in the bottom and still melting ice cream on the top.
Good Luck!
Jim | 
Frigidaire hot on top cold on bottom 
