Fridge freezer not cold

[vikki_78]

I've just bought a second hand fridge freezer which was working fine when I went to view it, now that I've got it home it doesn't seem to be getting very cold, I've let it sit for 3 days to settle but it's not working properly. The fridge if anything is actually warm and the freezer at best is as cold as the fridge bit should be. I'm not sure of the model number (it's a Hotpoint and is either a RF61 or a RF21). The light comes on in the fridge so it's definitely getting power but short of buying another one I don't know how to get it sorted - any tips?