Sounds like the truancy officer needs to put on his/her big boy/girl pants and get the job done.
"Hi, I'm Officer So-and-so from the (Insert city name here) Police Department, and I'm here to speak to you about your son/daughter not attending legally-mandated schooling. So, realize your true potential, show some energy for a brief moment, and step your @ss out here so that we can discuss it like adults. And if you slam the door in my face again, I'll be back with several of my fellow officers, Children's Services, an arrest warrant, and one heck of a bad attitude. Trust me, you will not enjoy that experience. Now, tell me what your plan is to improve this situation. I'm not leaving until you have a plan."
I'm a retired USAF master sergeant and a former First Sergeant of a rapid-deployment fighter squadron. I'd love to serve as a police officer, not to abuse my authority, but to deal specifically with issues like this one.
Kev