Complete the on-line application for free child support services if you live in Illinois and the dependent child(ren) lives with you. Illinois Legal Aid Online provides a guided interview called an Easy Form that will help you fill out the forms.Calling the Child Support Customer Service Call Center at 1-800-447-4278 (persons using a teletypewriter or TTY device may call 1-800-526-5812); or. If spousal maintenance and child support orders are made together, Illinois requires those payments first go to the state. Remarriage won't impact a standard child support arrangement in Illinois. But after the wedding, your monthly amount might change. Gov or call 800.447.4278. Complete the fields below and press calculate to estimate alimony. Does the Judge follow this amount to a "T"? I live in Contra Costa County and my attorney mentioned that our county follows the Alameda formula.