Five flavors of Dumb

I read this a couple of years ago now, but I distinctly remember reading this book, really enjoying it, and then it just...cuts off. Whole subplots (or, really, one in particular) are completely dropped. It was so jarring that I ended up mad at the entire book. Mad at the parents, mad at Piper, mad at the band. I really needed a conclusion here.

Am I just remembering wrong? I may need to pick this one up again.