Support does not modify automatically in most states. You must take some action to get it changed. You will likely get credit for the time that the kids were with you and you were still paying, but that legal obligation must be corrected and changed by a court. Child Support enforcement is a very serious matter and when these issues are not dealt with at the time they occur, there are far reaching, long term implications and financial consequences for the obligor parent. It is critically important to have orders entered, and modified to reflect the actual circumstances in the children's lives. You should contact you local Child Support Agency. They will assist you in modifying the order, obtaining a valid order, and enforcing the order once it is obtained. Do not rely upon verbal agreements with the other parent, these are NOT enforceable and will not serve to change your court ordered child support obligation. There is no charge or fee of any kind to seek assistance from Child Support Services in your area.