Your question is a bit unclear. The duration of child support is set by law of the original state of issuance (in your facts, Missouri), so if "current" support ends there at 18, or 21, that is when support should have stopped -- you can and should contact the Missouri child support collection agency to verify that their records show this as an arrears-only case, and you should get them to send you the payment records so you can verify that you have been credited with all money you have actually paid. The other states are merely acting as collection agents -- the case is in, and from, Missouri. If you cannot get anywhere on your own, consider hiring a MO lawyer to assist you.
Answered on Dec 19th, 2014 at 11:17 AM