HOTPOINT MISTRAL FROST FREE FRIDGE FREEZER?

How can I fix my hotpoint mistral frost free fridge freezr? The monitor window is showing the fridge at +22 and the freezer at -22, the freezer is fine, but the fridge will not reduce in temperature even when using the control buttons to set the temperature as low as possible, we have checked that the door has not dropped and that the fan cuts in when the light is off, that is working fine. Would a new thermostat or evaporator thermistor rectify this fault?