Do you take any other method of payment besides a credit card?
Currently Vonage only accepts Credit Cards with a United States Billing Address as a form of Payment. Vonage will also accept debit cards with a Visa or Master Card logo. All debit cards must have a credit verification number on the card.
The above info was taken from the following website
http://www.vonage.com/help_knowledgeBase_article.php?article=363&categor y=197