has been over charged. we have details of the class action lawsuit. when you check a website or download a app you use data. and this man chose the smallest plan for mike, because he doesn t use his phone much. within days, he was surprised to find he had exceeded his limit, generating an over charge. even more surprising, what some call phantom charges. the class action lawsuit accuses at&t of systematically over charging customers. you know, everybody, we re not hearing the full compliment
reporter: even more surprising, what some call phantom charges. there s unusual activity on the bill in the middle of the night, when we re all sleeping. charges. they re data charges. reporter: the class action lawsuit accuses at&t of systematically overcharging customers. well, it s like a rigged gas pump where when you go to the gasoline station and you ask for a gallon of gas you only get 9/10. reporter: we asked john davis, a computer engineer who isn t involved in the lawsuit, to show us how much data is downloaded when you click on various sites. click on msnbc, it s a good deal larger than the google website. reporter: and most news sites are going to be larger, are they not, in terms of data usage? yes, they will be. ow, charlie! ow! reporter: click on a youtube video and it uses even more data. for this lawsuit the lawyers say they hired an independent computer firm to precisely