When I pay for a app that I did not want so I get my money back

Unknown Charge

• Curious about a Charge? --> If you see an 'itunes.com/bill' or an unfamiliar charge on your statement
• If you have an issue with an app on App Store or billing --> Request a refund for an App Store or iTunes Store
• You can also request a refund for a recent renewal of an in-app subscription.purchase 

We are just other Apple users here, no one here can issue you a refund.

You need to go through the steps outlined above.