Overpayments. To receive important letters about overpayment recovery waivers, please ensure your mailing address is updated in your IDES account. To make an installment agreement, you will need to talk with IDES' Benefit Overpayment Collection at (800) 245-9762 (TDD (800) 662-3943).If you were overpaid on unemployment benefits from the Illinois Department of Employment Security (IDES), you may not have to pay that money back. CHICAGO (WLS) People who received Illinois unemployment help during the pandemic are now being told they owe thousands of dollars back.