Owners of an express toll route in southern Ontario have been ordered to pay $50,000 in punitive damages to a car dealer for the way the company dealt with a dispute over allegedly overbilling the man.

Markham-based Daniel Min uses transponders, an electronic device that automatically charges customers for the distance logged, when he's ferrying his vehicles down the toll highway to auction.

But he says the 407 Express Toll Route's sensors didn't recognize his transponders, and billed him an extra fee charged to those vehicles using the highway without the device.

He didn't realize the device wasn't reading properly until he received a huge bill.

Min offered to settle for $8,000, but 407 ETR Concession Ltd. refused and passed his file over to a collection agency.

The company also pursued him in both small claims court and the Ontario Superior Court.

Every day, Min says he received three phone calls from the collection agency, even as the court proceedings were underway.

Min's lawyer, Paul Copeland, argued that the company mistreated his client and acted unprofessionally by harassing him.

"In both of [the cases], you run your business so badly," said Copeland. "You have a monopoly. Punitive damages should be awarded against you to make you aware that you are actually aware that you have a responsibility to deal properly with the public."

On Monday, a judge ruled that the owner of 407 ETR has a monopoly and substantial resources, and has a duty to exercise its power responsibly.

A company spokesman says it's reviewing the ruling.