Every utility engaged in any intrastate business in this state must file with the commission a true and correct statement, properly verified, of every outstanding or existing agreement between it and any holding company or affiliated interests, substantially affecting the financial status or credit of the utility, or the management or control of the utility by such holding company or affiliated interests. Thereafter, it shall be the duty of every such utility, within 30 days after the making thereof, to file with the commission a verified statement of every new agreement or modification of an existing agreement of like character; provided, that the commission may, by affirmative action, relieve any utility from the duty or obligation of filing any such statement. The commission shall have full authority and power to investigate any such agreement, and if the commission, after due notice and hearing, finds that such agreement is unjust and unreasonable, the commission shall make and enter such order as is just and reasonable relating thereto.