We noticed when we 1st moved into our home that the refrigerator was not cold enough. I called an appliance serviceman who told me to let it defrost and showed me how to check the error codes. If you do research you will find out that this is a common issue with Samsung refrigerators.
I bought the defrost kit from AppliancePartsPros.com and put it on myself. It came on the 2nd day. By that time my refrigerator was completely defrosted. It was not difficult at all. I am so glad I took this route. There are so many videos on YouTube that will walk you through the process. Fortunately, I was able to save myself 400 - 500 dollars.
I would also advise checking after a week or so to ensure the product is working. Other than that all is well.
Thanks APP,
RR