I have a Samsung side. I have a Samsung side by side refrigerator - model RS20CCMS. The problem is

Question

I have a Samsung side by side refrigerator - model RS20CCMS. The problem is both fridge and freezer not cooling properly - current temperation freezer 0 and fridge 15 and even with power cool wont go colder. Have emptied fridge, cleaned dust from the back - switched off and on again - any advice would be much appreciated. Thank you.