If a person served with a notice to treat does not within twenty-one days from the service of the notice state the particulars of his claim or treat with the acquiring authority in respect of his claim, or if he and the acquiring authority do not agree as to the amount of compensation to be paid by the acquiring authority for the interest belonging to him, or which he has power to sell, or for any damage which may be sustained by him by reason of the execution of the works, the question of disputed compensation shall be referred to the F1Upper Tribunal.