Possibilities are:1. Your credit card number, expiration date or verification code are not entered correctly. The verification code (or CVV) is a physical signature for the actual credit card you are holding and it will change when you receive a new card (with a new expiration date, etc.).  Please make sure you enter the correct CVV or verification code for your new card.2. Your address is not entered exactly as it appears in your billing statements. You should contact your credit card company to make sure all addresses associated with your account are correct.3. If you are still unable to complete a credit card transaction, please try using a different credit card.If you can not find the error, you can contact your bank and ask for the reason of the refusal. For any other questions, you can contact us at this email address: support@zumalka.com