As of right now, the billing info forms are NOT secure. They post to a http:// url, not a https:// url. This means that anything you enter in those forms are sent in plaintext across the internet. If you have not entered your info, I suggest you wait untill EI has a secure form and site set up. If you already have, keep an eye on your statements for any unusual activity. (you should be doing this anyway)
And yes, I did send email to EI about this.
What is https? How is it different from http?
http or hypertext-transport-protocol is the standard by which your web browser communicates with a web server. The contents of the communication is in plaintext, meaning that if you sent or received "This is a message", a 3rd party can intercept that communication and find that it contains "This is a message".
Traffic sent over a https connection is encrypted on the other hand, meaning that a 3rd party intercepting the traffic will not be able to figure out what it says (within a reasonable amount of time -- on the order of decades or longer). If you sent or received "This is a message" over an https connection and someone intercepted it, they'd get a bunch of garbage, and it would take them a VERY long time to figure out what was sent.
https also has identity verification. Part of the encryption setup involves a site certificate. This is a bit of code that will help you determine if the site you are visiting is the one you want to be giving your information to. Double click the "padlock" icon near the bottom of your browser window and look at the site identity. This should tell you the company that owns the url you're visiting (such as "EI Interactive"), as well as some body of authority (such as Thawte or Verisign) that has verified the identity of that company.
ALWAYS make sure you are using a form hosted on a https url which posts to a https url (your browser should alert you if you are using a https form which posts to a http url) whenever you are entering personal or financial data.