Upright freezer is not freezing correctly. The 1st shelf is the only one that freezes, while the middle & bottom shelf are not frozen. Was working fine till last week, so defrosted the freezer thinking that it might solve the problem, but its still not freezing then entire freezer.
I am assuming that the compressor runs all the time.
Sounds like the unit is low on freon so you are only getting minimal cooling on part of the evaporator coils.
This will be an expensive repair as you need a pro.
Also there is no use in adding freon unless the leak is found and repaired and there is no guarantee on this.
Usually it makes more sense to put the dollars towards a new unit.