AT&T have begun their pre order for the iPhone 4, which ran out of stock on the first day and experienced technical difficulties. And it doesn?t end there, according to Gizmodo the order system has been giving out existing users? information to those who login to order a new iPhone.

Customers are finding that when they login with their own credentials they are taken to the account of another user. Which gives access to private information of the other user, such as address, call details and billing information.

An AT&T insider has been speaking with Gizmodo, and has revealed that the issues may be linked to an update applied to the AT&T server which was done with no testing afterwards. The insider said:

"[...]Over the weekend there was a major fraud update that went down on all of AT&T’s systems, from Saturday overnight to Sunday early morning. All systems were down and agents were unable to use any systems.

The issues people are seeing at AT&T stores and online are most likely related to this update that went wrong.

I do know that there was absolutely NO TESTING of this system done before the launch of the new iPhone. I know it’s just heresay at this point, but I can confirm that there was a major outage over the weekend that impacted all ordering systems and programs, and I can confirm that there were multiple systems being upgraded/updated, with some updates being related to fraud.[...]"

The issue happens whether a user logs in or not, so there?s no way to guarantee the safety of any details. AT&T have taken the system down since Gizmodo revealed the issue. There has been allot of response to Gizmodo?s article by users who have been affected, Apple and AT&T have yet to do the same. You can read the article and comments here.