Child support collection issue

Have order for 109 wkly since 2000 with 30,000 in arrearing. Recently another woman has put my son father on child support and my court order has not been changed but my check amounts are now bouncing between 30 to 100 a week average 60 a week. Child support office here in florida said there is nothing they nor I can do about it. Is this true. How do I collect on my arrears. Plus I put in several request for the judge to change my order, because my ordered amount is hendering me from government assistance like foodstamps, stating my income is too high, but they refuse to change it, states my case is fine the way it is. What do I do. I know there were multiple questions here, but please help me, I'm desperate.