You are receiving card authorisation failed or payment declined messages when trying to purchase the applicaiton via Google Play Store.
Please log in to your Google Wallet account at https://wallet.google.com and click on 'Payment Methods' on the left hand side. Please ensure that your card details are correct and edit, or add a new card, as necessary. You may then repurchase the app via the Google Play Store.
If you continue to receive authorisation or payment declined errors, you will need to contact your card issuer for further information.