Refrigerator side not cold. Freezer fine.

Our refrigerator side is not working. We have done a lot of trouble shooting. Evaporator fan is working. Damper control appears to be the problem. Unit has now been unplugged for 24 hours.we did have a little ice buildup in freezer at top right corner. We question if it’s only the damper control. When cleaning freezer now that it’s empty we noted the evaporator coil tray looked dirty but on closer inspection we saw that has rusty and peeling paint. Does that indicate another part of the problem and if so, what would that be?