Issues with child support order and father not obeying?

My sister and her ex-husband have been divorced for 3 years. The court order stated that they would share physical custody of their 3 children. In lieu of child support (her ex-husband makes twice her income) he would pay $15,000 a yr in expenses for travel ball for her two boys. His argument to the court was that they were certain to gain schlorships, etc. and the travel baseball was an investment in their future. My sister was completely against this bc she needed actual MONEY to help support them and travel ball was not a necessity. This drug on for over a year and she ran out of money to keep fighting him. The result was that she agreed to the deal. She would get no actual child support money, but he would spend $15,000 a yr on travel ball and also have the kids 1/2 of the time. Since that time, he has pulled them from travel ball completely and only gets them 1 to 2 days a week, if that. My sister is 100% responsible for their finanical upkeep when it comes to clothes, housing, food, etc. He only pays for their health insurance and meals when he has them. She hired a new attorney a few months ago but still hasnt been able to get anywhere with this situation. Her ex-husband has repeatedly found ways to put off the court date. His most recent way was to refuse her attorneys request for his work income info, which resulted in a subpoena for the info and a new court date being set. Just today, he sent her attorney a "discovery request" document asking her a million financial questions. She is more than willing to answer the discovery request but also knows he is doing this to keep putting off the court date. I feel like she needs a new attorney. I want to know if anyone has ever heard of this type of arrangement and also how someone can completely NOT do what a child support order states and get away with it. I know if my sister had been awarded a DIME..child support recovery would be all over it. What should she do to get help in this situation? IT seems like there is no answer for her. Any advise or suggestions would be greatly appreciated and I will share them with her. Thank you