Citing allegations of systematic overcharging a California man has filed a class action lawsuit against AT&T.

Calling AT&T's billing system a rigged gas pump, the filing says AT&T overstates its users' data transactions.

The full extent to that overstating was discovered by a consulting firm that found out that, over a two month span, AT&T bills overstated traffic up to 14 percent. Barry Davis, the attorney for the plaintiffs, says the complaint is thus far only about iPhones and iPads.

The filing also accused AT&T of charging customers for so-called phantom traffic, the name given to small amounts data with no clear source. Over a ten-day span the consulting firm found that AT&T was had charged for thirty data transactions, even while all applications and notifications were turned off.

This is like the rigged gas pump charging you when you never even pulled your car into the station, the filing says.

AT&T spokesman Marty Richter emphasized AT&T's commitment to transparent and accurate billing, noting that AT&T provides ways for customers to keep track of their accounts. We've created tools that let our customers check their voice and data usage at any time during their billing cycle to help eliminate bill surprises, he said. The company plans to defend itself vigorously, Richter said.

Phantom data has been a problem for other smartphones as well; Microsoft says it is releasing a fix for Windows Phone 7, which caused the Yahoo! mail client to pull more data than necessary.

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