I have a Candy combined fridge freezer purchased second hand a year ago. I think the model no is CP2411F/9. Frost free model but freezer section completely freezes over where it drains requiring defrosting. The freezer seems to work fine (currently -30 c) but the fridge is too warm. I have defrosted it but the fridge is still too warm 3 days later (15 c). Is this a fixable problem or is the fridge just worn out and I need to buy a new one?