Schreiber Integrated Fridge with Freezer Compartment?

Just bought a new house which has a Schreiber integrated fridge with freezer compartment. Unfortunately there was no manual but I didn't see this as a problem. Fridge is model number 2004027396 and my problem is that I dont know what number the dial should be set at for the freezer compartment to be frozen and the fridge to be normal. At the moment freezer seems to be normal fridge is freezing everything. Don't know if appliance was used by previous owners. It was left to run a while before food was added. Moving the dial between 0 and 5 doesn't seem to be making much difference although I may not be giving it enough time. Do I need a new thermostat or new fridge? Please help me as we have wasted quite a lot of food because of this.