How do I defend counterclaim for child support when counterclaim is false?

It sounds like the counterclaimant is seeking a retroactive modification (decrease) of child support and therefore a credit toward the arrears based on a change in the parenting time schedule some time ago.  You have several arguments that you can bring to the court's attention to aid the court in making a determination in your favor, including, but not limited to, the fact that your 17 year old continued to reside with you during those 20 months and you remained the child's parent of primary residence or primary residential custodian during that time.  During those 20 months, you still had to maintain a room for your child; have heat, electric and water for your child; have food for your child; buy clothes for your child; pay school fees for your child; and more. The counterclaimant's child support obligation to you during that time did not stop.  You may also rely on New Jersey court rules and statutes to argue that the court should not modify child support prior to the date that you filed your application. Generally, when a motion to modify child support is made, New Jersey's "anti-retroactivity statute" only allows a modification in child support retroactive to the date that the motion was filed.  Hence, another argument is that if the counterclaimant wanted a modification of child support back then, s/he should have filed an application back then.  At this point, you may argue, the "anti-retroactivity statute" prevents the court from modifying child support prior to the date you filed your motion.  Another argument is the doctrine of laches, which essentially means too much time has passed now and any retroactive modification of child support would be prejudicial and inequitable to you. There may be other arguments available to you depending on the unique circumstances of your matter.  The attorneys at Weinberger Law Group offer a free one-hour initial consultation and are happy to discuss your options with you.  Call today to schedule your free consultation.  You may also find the below websites to be informative: http://www.weinbergerlawgroup.com/children-parenting/child-support/modifications-amendments.aspx http://www.weinbergerlawgroup.com/children-parenting/child-support/enforcement-recovery.aspx