I read your question - you state you have full custody - that means that you can take control of your daughter - it appears that your ex is in violation.
Per my legal experience, you can take him back to court (modified order) and advise the court that he is behind in child support payments. With respect to the school issue - if your daughter is with him because of the schooling - the court will see to it that he abides by the order (to fulfill his role, accordingly, in having temporary custody) - therefore, taking him back to court is the way to handle this matter. Or, if you wish to stop his rights to temporary custody because of his actions, you can advise the judge - and, if so, you may wish to ask that your ex have monitored visits of your daughter - to eliminate further problems.
If you wish for further information, please let me know.
Peace, Love & Happiness,
The Mystic Wave