I am trying to top up but when i put in my credit card information it isn't completing the purchase
It's seem all of your orders has been rejected by payment gateway due to authorization issue. You may try to place a new order again or you can contact your credit/debit card for more information regarding this matter.
how do i fix it
In case the problem persists, you will need to contact your Bank or Card issuer to inquire further about the authentication/authorization of the payment from your card.
You're welcome. Kindly contact us at firstname.lastname@example.org should you need any further assistance.