I want to put in a counterclaim for an increase on a modify petition by the ex. He has gone on numerous trips in 2017 but is claiming to have no money

Ex has gone numerous trips including living in Grance for 5 months but is claiming he can't pay child support. A default order was entered in on January 29, 2018 because he didn't show up to court for the second time. He put in a petition to modify this order to decrease it and to temporarily suspend the order so he can catch up on arrears. He has made no effort to help support his daughter or to get a job. He's also claiming that he supports his other child but he has a support order for that case that he also does not pay. He's basically skating by without paying while living in a $1600 apartment, going on trip, eating out at expensive restaurants. I would to respond to petition with a counterclaim of an increase in support and also put evidence of him going on trips (text messages, pics) I'm not 100% sure how to proceed.