(a) A residential tenant shall be entitled to recover damages from the landlord for the utility bills rendered in the tenant’s name as a result of the landlord’s violation of this Act and which the landlord has not paid to the utility company. The tenant shall have the burden of establishing that the tenant was billed for utility service as a result of the landlord’s violation of this Act. Upon proof by the tenant that the tenant was billed an amount for service not attributable to the unit or premises occupied by the tenant, the landlord shall be liable to the tenant for 100% of those utility bills. However, this sum shall be reduced by whatever percentage of use that the court finds that the landlord has established to have been attributable to the unit or premises the tenant occupied during the period that the violation continued. The tenant may recover these damages by an action at law or by a counterclaim in any action brought by the landlord against the tenant. The court may treble the damage award when the court finds that the landlord’s violation of this Act was knowing or intentional. The tenant may also recover costs and fees, including attorneys fees, if the amount awarded by the court for utility service is in excess of $3,000. The remedies contained in this Act do not limit or supersede any remedies the tenant may have under a lease, contract, or the laws, including the common law, of this State.
     (b) This Section shall be prospective in application; the remedies shall not attach to any violation that occurred before July 1, 1992.
     (c) Nothing in this Section affects the relationship between a utility company and its customers.