Child support question?

Sorry, if this a little long. Deal is, I am custodial parent of my 2 boys, ex was originally ordered to pay 700$ a month child support in divorce, very soon after divorce he lost his job and with the new job he would have to pay 450$ month based on the the percentage for our state at the time. It also stated in divorce that child support was to be paid directly to me. Which was fine, he paid his support, occasionally got behind but always caught back up. Then year later he quit his job and continued to change jobs about once a year, but continued to pay the 450$ a month regardless of job he had always telling me his income was the same. Ok, well in order to maintain peace and keep things friendly for the boys sake I accepted it and moved on. Flash forward a few years and he gets remarried and loses his job again. He basically stopped paying me which left me no choice but to start the court process and have it go through child support services. Through them I found out that he never went to court and modified his income for all those job changes and now they are saying hes behind. My case worker has not been helpful in answering questions and I have no idea what to expect when we got to court. If anyone has any similar experience and let me know kind of what to expect I would appreciate it. thanks.