I accidently paid for an app

Clickhereand ask the iTunes Store staff for a refund.

(134525)

You may find one of the choice selections in this Apple Support topic 'iTunes'

a path to investigate to further adjust the issue with someone at Apple directly:

The links work best if you are already logged into the Apple ASC or support...

http://www.apple.com/support/itunes/

https://getsupport.apple.com/Issues.action

Since the above reply with great link was not showing before I added my reply

that seems to be a fine way to directly address your situation...

They should be able to re-credit your account.

Good luck in this matter! 🙂