Stephanie Oliver, there’s a chance that there is a leak in the sealed system. There too many things that will cause a refrigerator not to cool, it makes it impossible to diagnose without being at the unit. But if I went on a job and the same issue as yours, I’d be looking for signs of oil near the compressor or condenser. If there’s oil then there’s a refrigerant leak. I’d also check for frost building up inside the freezer on back wall or the freach food section too. Also, do you hear the fan/s inside the unit and one fan by the compressor. Are the coils underneath dirty?