((a)) ** Filing; public display** Every common carrier, except connecting carriers, shall, within such reasonable time as the Commission shall designate, file with the Commission and print and keep open for public inspection schedules showing all charges for itself and its connecting carriers for interstate and foreign wire or radio communication between the different points on its own system, and between points on its own system and points on the system of its connecting carriers or points on the system of any other carrier subject to this chapter when a through route has been established, whether such charges are joint or separate, and showing the classifications, practices, and regulations affecting such charges. Such schedules shall contain such other information, and be printed in such form, and be posted and kept open for public inspection in such places, as the Commission may by regulation require, and each such schedule shall give notice of its effective date; and such common carrier shall furnish such schedules to each of its connecting carriers, and such connecting carriers shall keep such schedules open for inspection in such public places as the Commission may require.

((b)) ** Changes in schedule; discretion of Commission to modify requirements**

((1)) No change shall be made in the charges, classifications, regulations, or practices which have been so filed and published except after one hundred and twenty days notice to the Commission and to the public, which shall be published in such form and contain such information as the Commission may by regulations prescribe.

((2)) The Commission may, in its discretion and for good cause shown, modify any requirement made by or under the authority of this section either in particular instances or by general order applicable to special circumstances or conditions except that the Commission may not require the notice period specified in paragraph (1) to be more than one hundred and twenty days.

((c)) ** Overcharges and rebates** No carrier, unless otherwise provided by or under authority of this chapter, shall engage or participate in such communication unless schedules have been filed and published in accordance with the provisions of this chapter and with the regulations made thereunder; and no carrier shall (1) charge, demand, collect, or receive a greater or less or different compensation for such communication, or for any service in connection therewith, between the points named in any such schedule than the charges specified in the schedule then in effect, or (2) refund or remit by any means or device any portion of the charges so specified, or (3) extend to any person any privileges or facilities in such communication, or employ or enforce any classifications, regulations, or practices affecting such charges, except as specified in such schedule.

((d)) ** Rejection or refusal** The Commission may reject and refuse to file any schedule entered for filing which does not provide and give lawful notice of its effective date. Any schedule so rejected by the Commission shall be void and its use shall be unlawful.

((e)) ** Penalty for violations** In case of failure or refusal on the part of any carrier to comply with the provisions of this section or of any regulation or order made by the Commission thereunder, such carrier shall forfeit to the United States the sum of $6,000 for each such offense, and $300 for each and every day of the continuance of such offense.