The lawsuit, filed in federal court in California, claims that AT&T has been charging customers for data that they never used. Evidence for the claim was gathered by a consulting firm that has said AT&T inflates data use by as much as 7-14% and sometimes 300% to bolster revenue. The lawsuit only applies to capped data plans, and also appears to be limited to iPhone and iPad contracts.
An AT&T spokesman has responded to the lawsuit by saying, "We have only recently learned of the complaint, but I can tell you that we intend to defend ourselves vigorously. Transparent and accurate billing is a top priority for AT&T."