I would like to be refunded for an accidental purchase by my daughter

For future reference, make it difficult/impossible for your daughter to make purchases. In iOS 12, this setting is pretty heavily buried.

Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases. Tap Always Require for the password preference. Your daughter will no longer be able to purchase apps, or make in-app purchases without knowing your Apple ID password.

I don't think any business returns accidental purchases. If Apple is not agreeing to refund then you may have to deal with them not here.

You are responsible for securing your device and your account so that your children do not make unintended purchases.

If Apple denied the refund, then you're not getting your money back.

If Apple denied your request, there is nothing that you can do. You are not getting the money back. Keep a closer eye on your daughter or take her device away from her.