Gap does not allow intl credit cards. They only accept US issued credit card.
You need to order through conceirge. For vPost there's a 5% service charge for that.
Do you have Citibank credit card? If yes, just use BorderLinx. Their conceirge service is free. Plus after they order for you, they'll take note of the shipment for you. You dont't have to order then inform them at all.