CLEVELAND, Ohio -- Verizon Wireless, the nation's largest cell phone company, may refund thousands or even millions of dollars to customers because of problematic "data usage" charges.

Verizon, with 84 million customers, also is making changes in staff training, internal procedures and customer service after a Plain Dealer column Aug. 15 revealed widespread billing problems.

The Money Matters column chronicled the writer's six-month ordeal with $1.99-per-month data charges and the possible causes given by Verizon's customer service workers. All, it turned out, were wrong or only partly true.

More than 400 Plain Dealer readers responded to the newspaper with complaints similar to the ones in the column. The readers collectively pay for more than 1,000 phone lines. In addition, calls to customer service and visits to Verizon stores increased noticeably after the column.

Take a look at your bill

Where to look for the data usage charge:

The first page of your bill should have a section labeled "Quick Bill Summary." Look under the summary for "Usage Charges, Data."

What to do if you spot an error:

Call Verizon customer service (800-922-0204) or visit a full-service store to investigate the charges and ask for a credit.

If Internet usage is the issue, ask technical support to track down the Web sites visited, and dates and times.

If premium text messages are the issue, determine whether you have applications that are downloading information automatically. Go to your "menu," then click "media center." You may need Verizon's help determining what applications cost money.

You can block features you don't use and don't want to be charged for by accident, such as Internet access or the weather forecast. Access your account

online

, call customer service or visit a store.

At a minimum, thousands of customers apparently have been charged $1.99 per month for Internet "data usage" even though they had not tried to go online. In some cases, customers were charged when their phones were off, the batteries were dead, the phone's Internet access was blocked or even when the phones didn't have the software to go online.

Verizon vows to work with every customer nationwide who complains about unknown data and text charges. The company is prepared to give customers refunds retroactively, which could amount to a few dollars or more than $100 per phone line, depending on the extent of the issue.

Roger Tang, region president for Verizon, said Monday that the data charges were not a trick.

"We don't want to zing stuff into people's bills in hopes they don't catch it," said Tang, who's in charge of services in Ohio, Pennsylvania and West Virginia.

"We're not interested in charging customers for things they accidentally access. Our brand reputation is everything."

Of the faulty explanations from Verizon's customer service reps, Tang said, "Clearly, you identified a training gap I have to address."

Verizon doesn't yet know all of the possible causes for the $1.99 charges. Executives are investigating complaints on an individual basis and are tracking patterns. Some charges might be caused by a customer hitting a series of buttons and inadvertently accessing the Internet. Others might result from an automatic download for a service the customer may not realize he has.

How to block

Verizon says the company may not have done enough to inform customers what can be blocked - and what the customers can do themselves by accessing their accounts online.

Here are features that you can block:

• Application downloads

• Premium texting

• Web access

• V-Cast music

• Mobile TV

• Text-messaging

In addition, as a service to parents, Verizon allows the account holder to turn capabilities on and off - for example,

blocking a phone

from being used for calls after 10 p.m. or for text-messaging during school hours.

Parents also can track their child's whereabouts through a service called

"chaperone."

If the child's phone leaves certain boundaries - say off a certain street - the parent is sent a text message.

"There's work now being done at the ranch," said Tang, who, along with three other Verizon executives, met with The Plain Dealer for more than 1½ hours Monday.

Verizon vows to work with every customer nationwide who complains about unknown data or text charges. The company representatives said they don't know how widespread the issues are but believe they're nationwide.

"We're taking this one step at a time," said spokewoman Laura Merritt. "We're still digging."

Hundreds of Verizon customers told The Plain Dealer that they got the same incorrect information both in stores and from customer service workers in call centers.

Some readers say they've been battling the charges for more than a year. Most said they're tired of calling Verizon month after month. Some were irate because they'd punished their children because they wrongly believed the kids had gone on the Internet. One reader said his mom's phone was charged for Internet access - weeks after the mother had died and her phone sat idle in her empty home.

Karen Fullerman of Twinsburg is typical of customers who complained to The Plain Dealer last week.

Fullerman has three phone lines; two are for her 23-year-old twin daughters. Fullerman has been charged $1.99 on one or two phones every month. And sometimes there's an extra $9.99 download fee. Fullerman, who recently lost her job, said every dollar counts these days.

She insists that none of the three has gone on the Internet. And she said Verizon has told her repeatedly that the company has blocked the phones' ability to go on the Internet - yet the Internet charges continue.

The same is true for James Grega of Brunswick, whose four phone lines with Verizon have been getting charged sporadically for about four months.

"The phones are still being charged after I had them blocked," Grega said. "Their assurance that the $1.99 charges would stop has been a joke."

Also frustrating to customers are several incorrect statements from Verizon workers:

Verizon can't determine the dates or times of supposed Internet access. The company can, said Joseph Hall, an associate director of customer service for Verizon.

You can't block a phone's ability to access the Internet without blocking the phone's ability to send pictures. You can.

A a $1.99 data usage charge could be caused by the company's "backup assistant" service. It can't; the service doesn't involve data usage and is a different line item for subscribers.

The company can't refund charges beyond the current month. "We do it all of the time," Hall said.

Brian Forneris of Amherst has made a mission of complaining every month he's hit with $1.99 data usage charges or $9.99 premium text message charges.

"I had success for a few months with getting Verizon to remove/credit the charges," he said. "However, they have refused to do so some months. I suspect that they hope that people will not dedicate the time and effort to wait on hold and argue for a few dollars."

Ferneris is standing on principle and talked to them as recently as last week.

"They continue to claim that they cannot block the ability to access megabyte usage without also blocking text messaging capabilities."

Hall, the customer service executive, said customers shouldn't be able to get charged $9.99 for premium texting by accident. The process requires a "double opt-in," meaning the customer must provide her phone number to a third party (such as an online IQ test or daily horoscope update). Then, the customer must respond to a text message sent to the phone to agree to the charges.

Some customers say they've never given such consent.

Besides increasing worker training, Verizon will change one policy as soon as possible to cut back on Internet charges incurred through hitting the wrong buttons. The default home page for most phones is Verizon's Web page. The company is changing its policy to not count visits to the home page as Internet time, Tang said.