Freezer wont go below 30 fridge at 40 to 45

Question

2 weeks ago the freezer stopped freezing, both  fans working, i cleaned the coins in the rear, removed the freezer back panel ( there is ice only on 1 coil from the bottom center traveling to the right up till the end where it reaches some device ) I dont know if this is the supply of return however it is not the line with the thermostat attached.  Please help. only a few years old.