I can understand your concern. The information you have received is good but this may be a different problem. If the freezer is only getting down to 20 degrees, this is not cold enough. At this temperature, the fridge section normally, will not cool sufficiently. The freezer should be down to between 0 - 5 degrees.
Now, if there is a heavy frost build up in the freezer on the back wall, this will be a defrost problem. As the frost gets thicker, both sections will get warmer. If there is no frost accumulation, this would appear to be a seal system problem. A technician will be required to make this type of check. I'm listing a site you can access, to have a tech come out. Here is a link for the website:
Sears Home Services
. If you would like more assistance, any additional details will be helpful and I will be glad to assist you further.