chould Education cost be included as a part of child support?

A few ago,H paid child support, medical payment and half of cost for musical classes.But now he refused to pay the class fee. He said the education was not included in his order.I hate that I didnt know these and it was not written in the order clearly. But it was him to ask to send kids to class orally and he paid half when I asked for it.

Now he stopped payment on these class while I am still sending kids to classes.

Is it possible for me ask for it through court order?

If I can't get the arrer back, can I ask to modify the order and include the education payment half half clearly? Does it help to go though a trial if he wont agree?

We both make good money. I think our kids deserve it. Is it possible I request to send kids to private school since he doesn't agree?

Thank you for your input!