How does the freezer work?

Hi,
I realise that this site is intended for professionals so please forgive me for asking this but I can't find anywhere else that may be able to help me.

I have a combined fridge freezer (freezer on the bottom) made by Candy. The unit has one compressor and one thermostat which is in the fridge. Its an old model and doesn't have a defrost facility.

I can't understand how the fridge works! The freezer seems to do all the work so I assume some of the 'cold' is moved up to the fridge. There are no coils / fans / ducts or anything in the fridge. Other than a tiny hole at the bottom (down which goes water to be evaporated in a tiny reservoir on top of the compressor) it seems to be nothing other than a plastic box.

Does the 'cold' come through the walls of the fridge?

Thanks for your help.

There is a cooling element (evaporator ) behid the rear wall of the fridge cabinet which is why you will get droplets of ice on the rear wall.

Ahh yes that makes sense. I think mine must be busted because the freezer works fine but the fridge doesnt work at all!

i think the thermostat is in the fridge compartment. There is none in the freezer.
So i don't think its possible for the freezer to work if the fridge isn't cold enough according the thermostat

The thermostat is in the fridge. The fridge is not cold so the unit keeps working constantly. The freezer is very very cold (-20) but the fridge is still only just under room temp.

There must be a shortage of refrigerant in the unit. A possible Refrigerant leak could be the cause of the fridge section not to work correctly.