Which payment gateway are you using? Which version of alidropship? Have you filled right API information? Is your website secure? Is your account activated? Well, provide more information so we can help
Yes, of course, you need a payment gateway account that processes credit cards, especially Visa, Mastercard and American Express. Depends on your country of residence, you need to choose the right merchant provider. About the FOC, I don't know, try asking your accountant.