A man looks at his phone as he walks past a Verizon wireless store in New York, July 30, 2009. REUTERS/Brendan McDermid

NEW YORK (Reuters) - The top U.S. mobile service, Verizon Wireless, has agreed to pay the U.S. Treasury $25 million on top of more than $52 million in refunds to consumers for overcharging them, the U.S. regulator said.

The venture of Verizon Communications Inc and Vodafone Group Plc said earlier this month it would pay refunds to 15 million cellphone customers erroneously charged for mobile Internet use.

The Federal Communications Commission chairman Julius Genachowski said in a statement the $25 million settlement was the largest in the FCC’s history.

“People shouldn’t find mystery fees when they open their phone bills and they certainly shouldn’t have to pay for services they didn’t want and didn’t use. In these rough economic times, every $1.99 counts,” Genachowski said.

Verizon said in a statement that the settlement was voluntary and it apologized for the “accidental data charges.”

It said the refunds amounted to about $52.8 million.