A federal class action lawsuit alleges "AT&T bills systematically overstate the amount of data used on each data transaction involving an iPhone or iPad account," Electronista reports. The lawsuit likens the situation to a tampered gas pump that "charges for a full gallon when it pumps only nine-tenths of a gallon."
Patrick Hendricks, who's named as the plaintiff in the suit, hired a consulting firm to investigate the matter. After a two month study, the firm alleges that Web traffic was frequently inflated by 7 to 14 percent, though sometimes as much as 300 percent. Because it's usually done in small increments, subscribers aren't likely to notice, though the cumulative effect could lead to a "significant portion" of AT&T's data revenues.

Hit the jump to read AT&T's response.