Zanussi fridge warm but Freezer ok?

Hi, recently my Fridge section of our fridge freezer stopped working….

Zanussi ZX79/5S1

I took the usual steps defrosted and cleaned it up but no luck. I removed the Thermostat so will test this at work but shouldn’t the fridge section still get cold without the thermostat? because it isnt.

When I removed the thermostat I noticed an air duct behind it so I guess cold air is constantly fed into this duct and the thermostat controls the amount of cold air into the fridge area?

The freezer section is perfect

any advice?

thanks!