Samsung Refrigerator not cooling (both freezer and fridge sides)
Start with manually defrosting the unit. Remove all food and place into another unit. Unplug the unit and allow it to defrost, with the doors open, for at least 24 hours. Make sure it is completely defrosted by feeling it and looking for any leaks of water. Once it is defrosted, plug it back in and monitor it for a few hours. Check for it to start, blow cool air, and chill inside. It could be that the defrost timer, thermostat, or heater have failed. This test will help to determine if it is potentially one of these things.

If it doesn't cool, see if you can manually move the timer. If so, will it now cycle? The timer is bad if you can manually cycle the unit, but it won't automatically cycle. 

Condenser coil frozen, could be either defrost heater, thermostat, or timer. 

If timer is ok and cycles properly, then see if it cools. If so, then you could have a thermostat issue that is not cycling the defrost heater. If the heater is not coming on, but the thermostat is good, then the heater is bad.

So see, it could be a number of things. But first, you gotta figure out if you can manually induce a defrost cycle.