Lying about daycare costs

I recently got a letter stating that my child support is going up by $300 for supposed work related child care costs. These are new costs and the cs agency has a letter stating the kids go. These are for a 14 year old and 10 year old. In asking my son, he denies any kind of daycare at all for either of them. They have never been in daycare before and I am pretty sure this is a lie. I have a court date in a couple months to argue this. What do I need to do? It’s not the support I argue, but just the bogus extra $300/ month that will put me over the edge financially. Thank you

I would request that the opposing party provide proof of the work related child care costs prior to the hearing so you have a chance to review it.