How do I report an accidental purchase and avail Refund?

Did you add money to your Account balance using this method?

Add money to your Apple Account balance - Apple Support

If that is the case, it may be possible to reverse the transaction if you did it by mistake. You will need to contact Apple directly to see if they will do that.

Contact Apple for support and service - Apple Support

Normally money cannot be transferred out of your Apple Account and it can only be used for purchases.

You will need to provide more information.

• Where was this done?
• How did you pay?

Using the link, you can either call or start a support request online using the button provided in the link.

Then I would suggest calling using the phone number for your region.