In cases of complaint of undue preference no damages shall be awarded if the Commissioners shall find that the rates complained of have, for the period during which such rates have been in operation, been duly published in the rate books of the railway company kept at their stations in accordance with section fourteen of the Regulation of Railways Act, 1873, as amended by this Act, unless and until the party complaining shall have given written notice to the railway company requiring them to abstain from or remedy the matter of complaint, and the railway company shall have failed, within a reasonable time, to comply with such requirements in such a manner as the Commissioners shall think reasonable.