The union representing Société de transport de Montréal (STM) bus drivers says too many payment terminals on the city's buses aren't working, meaning drivers are letting people ride for free.

Since Sept. 22, bus drivers have reported defective payment verification machines more than 13,000 times, according to the CUPE 1983 union.

That's the equivalent of 124 malfunctioning terminals each day, on average. And when the terminal isn't working, drivers let people on the bus for free, the union says. 

CUPE 1983 president Pino Tagliaferri doesn't believe the STM is taking the matter seriously at a time when it's facing financial problems.

"I don't think the future looks fine with the way the STM, and the direction of the STM, is being handled," he told CTV News.

The STM is forecasting a deficit of $78 million this year.

Last week, the service announced that it will no longer guarantee a maximum 10-minute wait on popular lines due to budget constraints.

For Tagliaferri, the situation is frustrating.

"You're letting on people [for] free, and at the same, you're cutting service for customers to get on board buses," he said. "One doesn't go with the other at all."

However, the STM disputes the union's figures, saying it's hard to know how the data was analyzed.

A bus driver with a malfunctioning payment terminal will report the problem at the garage, creating a service coupon -- but multiple service coupons can be opened for the same problem with the same terminal, the STM noted.

Nevertheless, the STM admits there's a problem with some machines and says the backlog for fixing them is limited to two garages.

"At these transport centres, the encryption keys needed to troubleshoot the ticket collection systems were no longer functional," a statement reads. "Since these are complex and custom-made instruments for the needs of the STM, the replacement time is significant."

The STM says they should receive new encryption keys shortly to resolve the situation in the "coming days."