Ge profile refrigerator. freezer temperature fluxuates -20 to +20 for a few days then thaws out

Question

freezer temperature fluxuates -20 to +20 for a few days then thaws out gets warm till i shut it off for about 3 hours and defrost. then will repeat cycle. other side works good till just before it thaws out then the lower half of frig freezes ( veggie drawer). not a side by side ,,but same problem with freeze and thaw...I have a GE 21cBRRWW made around 2000