State of Arkansas Letting Father Lie

I am a mother who allowed her son to move with his father from Texas to Arkansas. We both have joint custody still. When the move took place, I made a voluntary committment of monthly child support to help with expenses. In the order from Texas, I was to pay the father directly. I did this. I recently lost my job and became one month late on my "voluntary" obligation and the State of Arkansas allowed my ex husband to report that I had NEVER paid him. Now the state of Arkansas says that even if I could provide the money order reciepts I paid directly to him (per the Texas order) they could not say for sure that it was not a "gift". This is all BS!!! The state will however allow me to "modify" my amount because of a job change, so the joke is on my ex. According to state law, he will get less than half of what I was struggling to send. I don't live in Arkansas and just have to know: Is the CS Enforcement Agency a joke? or what?