§ 101. Unjust discrimination. No common carrier shall, directly or indirectly, by any special rate, rebate, drawback, or other device or method, charge, demand, collect or receive from any person or corporation a greater or less compensation for any service rendered or to be rendered in the transportation of passengers or property, except as authorized in this chapter, than it charges, demands, collects or receives from any other person or corporation for doing a like and contemporaneous service in the transportation of a like kind of traffic under the same or substantially similar circumstances and conditions.