Data overage charges crushing cellphone customers

American cellphone customers are paying more data overage fees than ever before. More than a quarter of AT&T customers and 20 percent of Verizon customers said they paid an overage charge in the past six months -- both records, according to a survey by Cowen & Co. The overage charges are exacerbated by tablets -- a record 24 percent of tablet owners with a 4G plan paid an overage charge.

The problem isn't going away: The wireless industry expects mobile data usage to double each year for the next several years. "I simply think our usage is outstripping our plans," said Colby Synesael, analyst at Cowen & Co