(a) All agents of railroad and express companies doing business in this state are prohibited from charging, collecting, or receiving pay for any goods, wares, packages, merchandise, or any article whatever that may be sent or received by or through their respective offices in excess of the regular rates charged for those articles.
(b) Any person who violates subsection (a) of this section is guilty of a violation and upon conviction shall be fined in any sum not less than one hundred dollars ($100) nor more than five hundred dollars ($500).