Can the school refuse to let me have contact with my daughter?

I have full joint legal custody of 2 girls, 12 and 16. The children's mother absolutely not even once has discussed anything with me about the children. She makes all decisions concerning medical, and schooling decisions herself. I don't even know what happens medically until I get a medical reimbursement claim from the courts that the mother submits several months after. Six months ago the mother sent my oldest daughter who was 15 at the time to a boarding school in another state without any talking to me, nor did she even tell me about it. It took me several weeks to track her down and when I did found much resistance from the school as their mother told the school that she has sole legal custody. I supplied the school with the court order stating I had full joint legal custody, yet the school does not inform me of any issues with my child still to this day. My question is can this school allow me to not have contact with my daughter? Her therapist at the school says she does not want to speak to me and will not allow me to speak to or have a therapy session over the phone. I have to write letters addressed to the therapist and have her read them to my daughter. She has had her wisdom teeth removed while at the school, again I was never told until weeks after it was done. She has emergency room visits for injuries that I am not notified of until weeks after it is already done, yet their mother is always notified immediately and makes the decisions alone as she has never once notified or discussed anything about my daughters with me. If I go to the school can they refuse to allow me to see the facilities and or my daughter? I am planning a trip to see the premises and my daughter very soon and they are trying to deny me this. I should say I was out of this daughters life for many years and spent the last 4 years fighting to get full joint legal custody of her. The school she is at is a residential treatment center for troubled teens.