CHICAGO (CBS) — Getting into a cab is supposed to be a convenience, but in some cases using a credit or debit card to pay for that cab can end with hundreds of dollars in overcharges.

Bridget Ryan planned ahead for a family birthday celebration followed by an evening out with friends at an Elmhurst bar. She’s been taught not to drink and drive, so she flagged down a cab for the two-mile trip back home.

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Her fare was $13.72, and she says she told the cab driver to include a tip of $4 on her debit card. The next day Bridget was received an alert from Bank of America that her account was overdrawn by $60. She checked online, and discovered the total cost of the cab the night before was $499.

“I freaked out,” she said. “You should be able to trust that if you give somebody your debit card, they can’t steal your money.”

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Bridget filed a complaint with Bank of America contesting the charge Her mother, Karen Ryan, who works in customer service for another bank assured Bridget she would succeed.

“I said to her, ‘Honey, It’s an absolute no-brainer, you’re going to get your money back,’” Karen Ryan said.

The bank did restore the money to her account while it conducted an investigation, but to their surprise, Bank of America sent Bridget a letter stating that “after a thorough investigation,” of her claim, “it has been determined that no error has occurred.”

The bank said it had been provided with documentation by the merchant “indicating a valid charge of $499,” signed by her, and the bank once again withdrew the money from her account.

Bridget informed the bank the signature was a forgery but the bank sided with the merchant and Bridget was once again out the $499.

“It’s two months of student loan payments,” said Bridget Ryan who now works for a suburban hotel. “It’s tons of money for me.”

She filed a complaint with the cab company, and the Elmhurst Police, with no immediate results.

“I don’t know when I have ever been so angry,” said Karen Ryan said. So she contacted CBS 2 Investigator Pam Zekman for help.

After CBS 2 contacted Bank of America about Bridget’s complaint, the paperwork was reviewed again, and her money was restored to the account.

The independent cab driver was identified as Gary Stilphen.

Zekman asked Stilphen how $500 could have been charged to Bridget’s debit card for a $13 ride.

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“No it was an accident,” Stilphen said, claiming it was a processing error.

A spokesman for the Elmhurst Police Department said records from the credit card company and the merchant have been subpoenaed as part of an ongoing investigation into what happened.

How often does something like this happen?

Records obtained by the 2 Investigators from the Chicago agency that licenses cab drivers show hundreds of passengers have complained in the last two years about credit card abuses and overcharges, totaling about $7,000.

Many victims said their debit and credit cards were swiped two, three and even four times for one cab ride. It typically happened, according to the complaints, when passengers were told their credit card did not process. The driver asked them to try another card or pay in cash.

Later the victims got their credit card bills and learned the charges did get processed.

A spokeswoman for the city’s Department of Business Affairs and Consumer Protection said it aggressively investigates cases in which passengers follow through with information needed to process a complaint.

Disciplinary action for cab drivers found to have intentionally overcharged passengers or engineered duplicate charges have ranged from fines to license suspensions.

But the spokeswoman said, “It’s extremely important” for cab riders who use credit cards to get a receipt, keep it until their credit card bill comes, and check the bill carefully to make sure there are no duplicates or overcharges.

That’s how CBS 2 reporter Susanna Song discovered she had been charged twice in one day for the same cab ride. One legitimate charge for $9, and a second charge for $50 that was not legitimate.

“I said, “Where did that $50 come from. That’s not something I racked up,” Song said.

She recalled that her cab driver was angry that she only tipped him 20 percent.

“He was saying that’s it? That’s all? This is all you’re going to give me,” Song said.

She filed a complaint with her bank, JP Morgan Chase, about the $50 charge, but much like what happened to Bridget Ryan, the bank responded that their investigation found the $50 transaction “to be valid,” because the merchant supplied a receipt for it supposedly signed by Song.

“There is no way I would have signed for that,” Song said. “It’s ridiculous, because it says that he drove me one mile and charged me $34.45 and tipped himself $12.55.”

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After CBS 2’s inquiry, Chase reimbursed Song for the $50 charge. Now the city is investigating what happened in Song’s case, because a preliminary investigation indicates that there might have been a problem with the credit card swiping device in the back of the cab which resulted in her account being charged for another passenger’s fare.