Rick -- Please call here +1 480 396 9700 and speak to Stephanie. She is out for the rest of this afternoon but will be here tomorrow. Like many other companies, we don't take AMEX but we do take Visa, Master Card, Discover, and PayPal. I can't say why John's card is being denied. The store will let orders at least register if the CVV code or address doesn't match. However if the card number is not valid, or the expiry date doesn't match with the number, or if the card is expired, or if the card is cancelled, it will not let the sale proceed.