My 561F SubZero fridge is not keeping the food cool enough. It is 50 degrees; freezer is 20 degrees. The door seal is damaged at the bottom. Repairman said it would be $250 to replace the seal and to start by cleaning the coils, which we did, and to use silicone on the seal, which is messy and does not restore the seal to a puffy state. The fridge is 8 years old. Thanks for any ideas or advice.