If you have trouble checking out, please contact us. When entering your billing address, MAKE SURE it matches the address on your credit/debit card. Also, make sure all of the card info (Number, Name, Expiration, Security Code) is an EXACT match before hitting submit. For payments at this time, we are only able to do PayPal invoicing. For any questions or concerns, please visit the FAQ'S page first. We have complete directions there. https://www.zachattacksupplements.com/pages/faqs