220 ILCS 35/6
A utility shall maintain records of deposits together with interest, which collectively will show all transactions pertaining to each deposit. A utility shall provide the applicant with a Certificate of Deposit for any deposit received. The Certificate shall show the applicant's name, service address, serial number, type of service, amount of deposit, rate of interest on deposit, date received, utility's name and a statement of the conditions under which the deposit will be refunded to the applicant. Nothing in this Act shall require a utility to accept deposits from third parties on behalf of an applicant.
In instances where a deposit is refunded a utility shall issue a Cancellation Notice carrying the same serial number as the Certificate of Deposit. When refunds are not deliverable, records shall be maintained to show a utility's efforts toward locating the applicant and delivering such deposit.
220 ILCS 35/6