We purchased a Samsung in July 2015. In March of this year the drawer freezer stopped working, as did the ice maker. Set up an appointment for them to come out to diagnose the problem. The service tech was here yesterday and did an excellent job of troubleshooting the problem. He thought it would be a simple part replacement (circuit board). As it turned out, it was a sealed unit problem and it would be very expensive. The refrigerator still cools, just not the freezer. He explained that the freezer and refer share the same compressor, the part that operates the freezer was clogged or not functioning properly. I assume there is a valve of sorts that changes from refer to freezer when necessary.
In essence, I am saying that Samsung is junk. DO NOT BUY! They should stick to cell phones and tablets. We have a Samsung Smart TV that we wish we hadn't purchased too! The frustrating part is that it was just over the warranty period. I am certain that I am not alone in this, when you pay over $2000 for a refrigerator it should last longer than just under 4 years!