When you try to re-install an app that you had previously deleted from your windows phone, you might get the error there are no refunds for this purchase. 

To resolve this, follow these steps.

1. Go to http://www.windowsphone.com, sign in,
2. Click on "My Phone" and then on "Account".
3. You should be able to find reinstall button for the app you want to reinstall

WARNING: Resetting your windows phone will erase all of your personal content, including apps that you purchased and downloaded, and restore your phone back to the condition it was when you first bought it.

You may want to reset your windows phone to factory settings if you found it not operating well, or forget your PIN. Also If you have a problem with the first Live account you used and wish to change it, you must completely reset the phone.

Reset Windows Phone to factory settings

1. From home page on your Windows Phone, flick left to the app list page
2. Tap Settings, then tap about
3. Tap reset your phone which located at the bottom of about screen.
4. When ask for reset confirmation, click yes

Reinstall APPs after phone reset

To reinstall applications that were purchased from the phone, apps must be repurchased from the Marketplace on the phone. When you select "buy", you should see the message "You've already purchased this app. Would you like to install it again?" Select Install to reinstall the application. You will see a similar message when purchasing free applications.