beko fridge freezer cda539fw

Hi people need help! 😕 I have a beko fridge freezer cda539fw on the inside of the fridge, and on the back of the fridge it has a sticker with number cda539fw2 with is supposed to mean that my particular model does not have a removable thermostat wire so the main compartment on the fridge freezer is the pcb fridgefreezer control module board, on the back of the unit. my fridge compartment is still over freezing I have turned the knob inside the fridge to minimum but still overfreezes I have looked on forum and they changed the pcb board and now it works fine.. But not for me I’ve put a new one in that I brought from this uk whitegoods but still no change. in the fridge compartment I have the dail thermostat witch is set at min where the light compartment is. i have unscrewed it only to reveal small wiring. I have turned the dial thermostat while it was unscrewed and it seems to be turning something inside the parts that it’s attached to, it does feel quite loose when turning though but doesn’t look broken.. So I’m frustrated as to what to do next I need to get it right so I don’t spend too much money repairing it! As I have brought a board (pcb) that I don’t really need!! Please help!