CHICAGO (CBS) — There are only a handful of people who get free rides on the CTA, and at the top of the list are employees.

So imagine one bus driver’s surprise when his debit card was charged for a fare.

CBS 2 Investigator Dorothy Tucker wanted to know how that happened, and why he didn’t get a refund.

The #9 bus down Ashland is a popular route for CTA employees returning to the nearby bus barn. It’s where bus driver Keith Ware boarded a couple of weeks ago and tapped his wallet.

Inside was his CTA employee card that allows him to ride the bus for free.

Only Ware was charged $2.50.

“Instead of reading my ID, it read my debit card,” Ware said.

Ware immediately called Ventra and explained one, he was a CTA employee, and two, his debit card is not on file with the company.

So why and how did they charge it?

“They told me it takes the first source that it can,” said Ware.

And because Ware had tapped his wallet to the reader with his debit card touching it first…

“It read my debit card. It took funds out of my debit card,” he said.

It’s the way the Ventra card works. But Ware had no idea.

It’s actually on the Ventra website, but you have to search to find it. Click on a link, then another, read a through a bunch of options and buried in a paragraph, an explanation that Ventra takes money from the first card it reads.

And the warning “…not tap their wallet.”

“It’s not fair,” Ware said.

And a suggestion from a man who works for the transit company:

“They should tell people. Put up a bulletin or something,” said Ware.

He wants his money back. Ware discovered he was actually charged twice for a total of $4.75. CTA said it is looking into the matter.

Ware said if CTA does not refund his money, he will file a dispute with his credit card company. Ware said it’s all about the principle.

According to the CTA, incidents like the one that happened to Ware have happened a handful of times.