http://www.getvpn.net/faq click on "What does payment verification mean?" :
"VPN providers suffer severe loss due to massive credit card fraud in this industry. Every new account payment is being checked manually to avoid fraud and once it's checked your VPN access is being provided. Usually it takes from one to few hours."
I found this when searching for a service that provides with a database that contains all ip addresses used by VPN providers, credit card processors use such databases too probably. I already use the ip-to-country and open-proxy databases to prevent password sharing and content theft. All suggestions welcome.