How Do I Modify My Child Support Payments

(Kansas)

In Oct. of 2009 I lost my kids to my x because I moved 20 miles away and because my kids slept with me some times. At the time we went to court my x knew he was losing his job yet he told the judge he didn't know. Of course 2 weeks later he was layed off. I have 2 children that I pay 948.00 a month child support and still continue to buy their clothes and provide all the insurance for them. how do i get that lowered now that he is living off the government at least until his unemployment runs out. i have always supported my children since they were born and have always carried the insurance on them. He only carried it the 2 years he was working. I have been on my job for 33 years so i hope I'm not screwed on being this guys meal ticket for the rest of my life. i will have my kids for the summer and will still have to pay him child support while i have them. I need some good advice. Thank you