How can unpaid child support be collected?
Try calling DCSS (Department of Child Support Services) toll-free at 1-866-901-3212 . They may be able to help with collecting the unpaid child support (called "arrears").
The DCSS web page on collecting/enforcing child support has information about different options available, such as income withholding.
The Court's Self-Help Center can help with filing a motion to determine arrears and ask for a wage assignment, so the arrears amount is paid directly from the employer to the person owed the child support.