Verizon has agreed to refund around 15 million customers which it overcharged for data use, forking out as much as $50 million in all.
Most will get between $2 and $6, though it will be substantially more for some. Refunds to current customers will be issued as credits on bills for October and November, with former customers receiving a check.
"As we reviewed customer accounts, we discovered that over the past several years approximately 15 million customers who did not have data plans were billed for data sessions on their phones that they did not initiate, said deputy general counsel Mary Coyne in a statement.
"These customers would normally have been billed at the standard rate of $1.99 per megabyte for any data they chose to access from their phones. The majority of the data sessions involved minor data exchanges caused by software built into their phones; others involved accessing the web, which should not have incurred charges."
She said the company has made changes to make sure it doesn't happen in future.
The refund follows questions from the Federal Communications Communication over the issue. But it may not be enough to satisfy the FCC, which could push for the company to pay a penalty as well.
The FCC says that it's received hundreds of complaints about overcharging over the last three years.
Verizon claimed a year ago that it didn't charge customers for data sessions where they'd launched their browser inadvertently and closed it down again right afterwards; the new statement seems to imply that this wasn't in fact the case.