Someone who is NOT paying their court ordered child support has given the department your phone number (or any number other than their own) as a tactic of trying to hide from the system as well as their legal and moral obligations for the care of the children they brought into this world. It's most likely someone you don't even know...they just randomly pulled a number from their hat and entered it into a form.
I got the same call and it's this random message about me owing child support...i'm a lesbian with ZERO kids, ever! don't want them, never had them and i don't need them. :)