How to modify child support in a state I no longer live

In 02/2006 my ex had his Alabama child support lowered due to temporary disability. He was ordered to notify the courts if this employment status changed. In 10/2006 he was arrested for internet solicitation of teen porn. I immediately sought to terminate visitation unless supervised and won.

I then petitioned the court to move to another state with the minor children and won. In 07/2007 my 2 sons and I moved to Missouri.

To make a long story short, I recently found out he has been back at his job for nearly 3 years (he will not communicate with me at all) and the visitation he was allowed to have has not once been honored. He was allowed to visit with his sons in Missouri with a 10 day notice, in a state approved location or someone I approved of.

The visit allowed was 1 hour per child for a total of 2 hours, he was then to leave the state. Every visitation would involve the above process. He has not seen his children since 07/2006, the year we left, and no attempt has been made to see them. The original child support order gave him joint custody with myself named as custodial parent.

In that order visitation was frequent and the support amount was based with that visitation percent calculated in.

So much has change now. One son is a full time freshman in college and the other graduates high school this year. Our original order states support is to be paid until they graduated from college and that he was to share in 50% of tuition,books,fees and room and board.

He has contributed nothing towards their education. All of this coupled with the fact that I am now the one temporarily disabled due to an on the job injury in 10/2011 and am facing back surgery next month from this injury.

Can I just go to the State of Missouri Child Services and ask for their help? Can they modify everything that needs to be modified up to and including the fact that he chose not to visit his children since 2007 and therefore 0% of time spent in his care should be factored into the amount he should have payed?

Can they enforce payment of arrearages from the time he reported back to work from his temporary disability leave?

Any help you can provide is welcomed.

Thank You,
Worried in Missouri

P.S. He just recently (2012) copped a plea on his porn charges and was given 8 years total confinement that was then suspended to 3 years probation. 2 of the 3 felony charges were dropped, the 3rd was dropped with his plea.

This guy is just above the law I guess, any other person would be serving the 8 years he was given with no suspension.