I think you have a few options. Take her to small claims court which will only cost about $30 to file and you will get your money back from the court. That court usually supports your position and you may get more then what the daycare owes you. You should also contact your state's licensing agency and file a complaint. If you want to go a bit further make a complaint with the BBB.org since she is a private business. Hope this helps.
https://www.daycare.com/states.html