Need advice on communicating with ex about parenting decisions

My ex just made a big decision about putting our oldest in private school without talking to me first. I found out from my daughter. Legally it's going through her so technically she can but it feels wrong to not discuss it. I don't want to blow this up and make things worse. How do people handle this? I've tried texting her but she's ignoring my messages. Do I need a lawyer involved or can we actually work this out?