When the commission is of the opinion that the interstate rates, charges, practices, rules or regulations of any utility are unjust, unreasonable, excessive, discriminatory or otherwise in violation of the Interstate Commerce Act, or other federal acts relating to utilities, or any of the rules and orders or regulations promulgated by the Interstate Commerce Commission or by any such federal agency or commission having jurisdiction thereof, the commission may apply by proper proceeding to the proper agency or commission for relief.