GE Profile fridge lost cooling everywhere except crisper draw

GE Profile fridge Model #GFE28HMHDES lost cooling everywhere except crisper draw. Sounds like compressor is running. I took the panel off in the freezer below, (back wall) and coils were not frosted over but the copper lines coming down from the top were. I left it off for a while to defrost and still not cooling. I need my fridge! Please help with any solution as to next steps in troubleshooting process, parts to replace, etc. Thanks in advance