Byron Fenoglio said phantom cell phone charges started to appear on his account in November.
"Hey I'm not using any wi-fi other than my home or Starbucks and they couldn't explain why," he said.
Fenoglio said he called AT&T and the company always gave him the same answer.
"Let me investigate. Let me put you hold for 2-3 minutes. They would come back. I don't see anything out of ordinary."
Now a team of attorneys has filed a class action suit in California. They paid a private consulting firm that uncovered that AT&T overstated data usage by 7-17% and in some cases more than 300%.
Barry L. Davis of Thornton, Davis & Fein, P.A is one of the attorneys involved in the case.
"We were stunned to discover that AT&T billed for a phone which was left untouched for 10 days, incurring 35 data transactions totaling almost 3,000 KB during that period," Thornton said.
Fenoglio said he saw a similar problem.
"I turned the wi-fi off on the phone, even that didn't work. Even with it totally shut off they still charged me."
Whiles Fenoglio said he’s been happy with AT&T until now, he is looking around and now weighing options.
"I'm going to do what I can to save money."
According to the complaint filed in California, AT&T reported a 27.4% increase in data usage during the fourth quarter of 2010. Attorneys in this class action suit said a significant part of that increase is because of the phantom charges.