CHICAGO (CBS) — Nearly 3,300 parking tickets have been dismissed in the city over the past two years because they were incorrectly issued, CBS 2 Investigator Pam Zekman found.

Zekman found that drivers who used the Park Chicago app incorrectly faced a ticket.

It happened to Loyola University student Laura Lucas, who used the app to pay the meter outside her class.

“I went to class knowing that I had the meter paid,” she said. “I got back to my car and I found the lovely orange envelope.”

Lucas had the receipt from Park Chicago showing she had paid four minutes before the ticket was issued.

If a ticket writer doesn’t see a receipt in the car’s window, the worker is supposed to run the license plate to be sure the parking fee has been paid with the app.

That didn’t happen in Lucas’ case and many others.

The 2 Investigators have found over the past two years, 3,279 Park Chicago app tickets have been dismissed by the city Department of Revenue because they were incorrectly issued.

“That number seems absurdly high,” said Minos Vlamakis, who uses the parking app. “Obviously they need to re-evaluate the app.”

Mike Brockway, of the Expired Meter.com, said: “It’s a combination of disconnects between the app user and the database as well as parking ticket enforcement people who perhaps aren’t doing their job as well as they should.”

Brockway says the Park Chicago program is running much smoother than it did when started two years ago.

“One wonders how many people get ticketed unfairly and just pay it or have to go through the process of fighting it through the administrative hearing process.”

Laura Lucas’ ticket was dismissed by the Department of Revenue.

“I’m still really afraid of getting a ticket, and I’ll always get out and check the first minute that I can get outside to make sure that I don’t have a ticket.”

City and Park Chicago officials say there are millions of app transactions a year and errors are a very small percentage of them. The city says it prefers no errors and will work quickly to fix them.

You can do that by calling 312-744-7275.