How can child support enforcement make you pay twice?

i am currently paying child support and have been for 4 years,they garnish my wages bi-weekly now they r trying 2 say i am delinquent in support and arrears,and r trying 2 make me pay twice 4 what i have already paid 4.they say they r getting the payments but have 2 see where it is being distributed and i need 2 pay the balance before they take judicial or administrative action.how is it that they can do this? they r taking half my check and i don't have the money 2 hire an attorney or 2 go out of state and take care of this problem.it's sad that the the people that r paying their debt faithfully and don't miss a payment can't live in peace, they make sure u have a miserable life!there should be a law against harrment. they need 2 stick 2 the people that are'nt paying and leave the ones that r alone! please if u have any advice or suggestions please leave one it would be greatly appreciated because i am stuck between a rock and a hard place. thanks!