OK, thnaks for that.
That's only surface ice you've got rid of.
You need to do a full defrost of the appliance.
(You can't just defrost the fridge, it's both fridge and freezer).
Empty the machine and unplug it.
Open the doors.
Leave it for at least 36 hours, in a warm room, to fully defrost.
Close the doors, plug it back in and it should work again.
If the fault returns within a few days, you have a fault in the defrost circuit of the fridge.
If this is the case, click here to find a local engineer
If you can't find a local engineer (Not a lot will work on Samsung products) then you could try the British Gas fixed price repair offer.
.Click here for the British Gas offer
Basically, your fan is likely jammed with ice.
This is why the cooling fails in the fridge.
See how it goes with the defrost and get back to me if you need more help.
Hope this helps