Missouri DCSE MO DCSE lied, opened a case that was closed and took money from my check for a child I have custody of and gave it to someone else. jefferson city, Missouri

I have 2 children , a boy and a girl of which both are teenagers now. In regards to the situation of child support for my daughter of whom which I have custody of.
In March of 2011 my ex requested to close our child support case due to the fact our daughter lives with me. We both did exactly what MO DCSE requested us to do with providing written notification to terminate the enforcement of our case so we thought all was good. Well now it is Jan 2012 and as of november 2011 MO DCSE reopened our case and notified me that I have $11,000 in back child support I have to pay and started a garnishment for 700+ dollars when in fact the original child support order was for 515.00. Find out that the reason they felt it was necessary to reopen the case because my ex was pregnant again and required medicaid to pay for hospital stay and delivery of her new son even though we were never married and the child is not mine and my ex even explained that to MO DCSE, and MO DCSE basically said someone has to pay the bills so why not me.

MO DCSE took 380+ from my check for her specific case and allocated only 34.00 to my daughters acct MO DCSE stated that under the new federal laws and guidelines they have the right to disperse the monies how they feel fit and they stated that they supercede any court order and that under this new law that they can change a persons child support amount as they seem fit as well. I asked for written proof of this law and guidelines and they said they will not share that info with me nor will they tell me where I can find this information on my own.
this is what they have on their site in reagrds to this :

On October 1, 2009, the Family Support Division (FSD) changed the way pastdue support payments are distributed among multiple orders for a noncustodial parent. FSD made the change to be more consistent with federal
regulations and state law. The result is a more equitable division of payments among all of a noncustodial parents orders, based on how much is owed for each individual order.
The below provides an explanation of how child support payments are distributed when a noncustodial parent is responsible for paying support on more than one order.  If the payment is not large enough to cover current support for all orders, the payment is divided among the orders, based on the amount of current support owed for each order. The order with the largest current support amount receives the largest share of the payment. If the payment is only enough to cover current support for all orders, the payment is credited to current support for each order.If the payment is more than the amount of current support owed for all orders, the excess payment amount is credited to pastdue support
owed on all the orders.The amount credited to pastdue support is divided among all of the orders based on the amount of pastdue support owed for each order. The order with the largest pastdue payment amount gets the
largest share of the excess amount.  --

As it is right now - MO DCSE realized they made a mistake and gave me credit for all of the arrearages except for 575.00 which was for the first month that I retained custody of my daughter.  so they said that the change in the order took affect 30 days after the day I retained custody not the day of. So even though I retained custody of my daughter on March 1st 2010 they are only giving me credit for april 2010 to present day and will keep my case open until I pay the 575.00. On top of all this they have two child support orders for the same child (my son) going to two different people of which one (his mother) doesnt even have custody of him , her ex husband does. this is crazy and i can now see how and why people snap and do stupid stuff when DCSE pushes them to the edge. they understand that our daughter is in my care but they still insist on taking child support from me and disbursing it how they seem fit.

I am looking for help with trying to figure this all out and to find out if everything they have been telling me is actually legit.