(a) It shall be the duty of every common carrier who has sold any tickets or other evidence of the purchaser's right to travel on its line or on any line of which it forms a part, if the whole of such ticket is unused, to redeem the same, paying the original purchaser thereof the actual amount for which the ticket was sold, or if any part of such ticket is unused, to redeem such unused part, paying the original purchaser thereof at a rate which shall be equal to the difference between the price paid for the whole ticket and the price of a ticket between the points for which the ticket was actually used, provided that such purchaser shall present such unused or partly used ticket for redemption, within six months after the date of its issuance, to the officer or agent who is authorized or designated by such common carrier to redeem unused or partly used tickets; and the officer shall, within 15 days after the receipt of such ticket, redeem the same as provided for in this Code section. Such redemption shall be made without cost of exchange or other expense to the purchaser of the ticket.

(b) Any person who violates this Code section shall be guilty of a misdemeanor.