So I had the same problem. This great article helped me fix the fridge with this replacement thermistor part, stop beeping constantly and the correct fridge temperature can be set again. The fridge now beeps as normal when the door is left open. All seems to work OK.
However, the Superfrost light and the right hand LEDs are still flashing on 3. The left LEDs have stopped flashing following the repair.
Would anyone know how to stop Superfrost flashing? Is my fridge permanently on Superfrost?