AT&T and Apple started accepting pre-orders for the new iPhone 4 yesterday, as expected. And while you could say sales were a total success, in reality the whole process turned out a complete debacle as neither company could cope with the demand. Apple reportedly logged more than 600,000 early orders, the largest number of pre-orders it has ever taken in a single day, imposing a strain on computer systems that prompted AT&T to take orders by pen and paper.

At roughly 5PM yesterday the carrier said it would stop taking pre-orders for the phone indefinitely so it could meet demand once the device actually launches next week, on June 24, and that it would reopen the process depending on how soon it can replenish inventory. Unfortunately for anxious would be iPhone 4 owners, it seems problems included not only server connection failures and general mayhem both online and in person, but also data leaks.

According to Gizmodo, the ordering system mistakenly presented users with other customers' account details, including their address, invoicing overview and outgoing phone calls. AT&T claims that they have been unable to replicate the issue and gave no official statement on what could have caused it. Gizmodo, however, reported that the failures and leaks were caused by a server update that "went wrong" last weekend and affected all ordering systems and programs.

This is not the first time AT&T customer data has been compromised. Just last week hackers managed to exploit a vulnerability on a web server of the U.S. operator to gain the email addresses of more than 100,000 iPad owners.