220 ILCS 5/9-252
When complaint is made to the Commission concerning any rate or other charge of any public utility and the Commission finds, after a hearing, that the public utility has charged an excessive or unjustly discriminatory amount for its product, commodity or service, the Commission may order that the public utility make due reparation to the complainant therefor, with interest at the legal rate from the date of payment of such excessive or unjustly discriminatory amount.
If the public utility does not comply with an order of the Commission for the payment of money within the time fixed in such order, the complainant, or any person for whose benefit such order was made, may file in a circuit court of competent jurisdiction a complaint setting forth briefly the causes for which the person claims damages and the order of the Commission in the premises. Such action shall proceed in all respects like other civil actions for damages, except that on the trial of such action the order of the Commission shall be prima facie evidence of the facts therein stated. If the plaintiff shall finally prevail, he or she shall be allowed a reasonable attorney's fee to be taxed and collected as a part of the costs of the action.
All complaints for the recovery of damages shall be filed with the Commission within 2 years from the time the produce, commodity or service as to which complaint is made was furnished or performed, and a petition for the enforcement of an order of the Commission for the payment of money shall be filed in the proper court within one year from the date of the order, except that if an appeal is taken from the order of the Commission, the time from the taking of the appeal until its final adjudication shall be excluded in computing the one year allowed for filing the complaint to enforce such order.
The remedy provided in this section shall be cumulative, and in addition to any other remedy or remedies in this Act provided in case of failure of a public utility to obey a rule, regulation, order or decision of the Commission.
220 ILCS 5/9-252