WASHINGTON  Verizon Wireless said on Sunday that it would pay up to $90 million in refunds to 15 million cellphone customers who were wrongly charged for data sessions or Internet use, one of the largest customer refunds by a telecommunications company.

The announcement came in a statement from Verizon Wireless as the company held talks with the Federal Communications Commission about complaints of unauthorized charges and in response to questions about a possible settlement of an F.C.C. investigation into the issue.

Verizon said in its statement that the customers would receive credits from $2 to $6 on their October or November bills or, in the case of former customers, refund checks.

The refunds will be paid to customers who did not have data access plans but who were nevertheless assessed one or more charges of $1.99 because of data exchanges initiated by software built into their phones, or because of charges for inadvertently going online on the phones.