I have a side-by-side GE Adora fridge. Every now and then we find that the top shelves in the freezer have thawed, while the bottom drawers in the fridge have frozen.

If we unplug it, it seems to reset itself and go back to normal, but then it happens again after a while.

My husband set it up on a timer to turn off every night for about fifteen minutes, and it was working just great for months ... but it's started again. It's happened twice in the last few days now.

Here are my questions:
What might the problem be?
About how much would it cost to fix it? (I'm talking ballpark range...)
Is it even worth trying to fix it, or should we put the money into buying a new fridge?

Thank you so much for any advice you can give. I'm so tired of losing drawers of produce to the freeze and having my freezer items refrozen into a solid mass after a thaw.