Can an airline unilaterally cancel airline tickets without getting the consent of the passenger/ticket holder?

A few days ago, Philippine Airlines sold $300 Business Class tickets from NRT/KIX-MNL-JFK/YVR/YYZ which the airline cancelled after a few days with an email to passengers saying the confirmed booking was identified as an “erroneous purchase transaction”.

What are the rights of the passengers / confirmed ticket holders? The amount appearing on the payment confirmation page was paid in full yet PAL is claiming that there was a glitch and would not honor the booking. So does that mean, everytime, PAL can just say there’s a glitch and cancel the paid and confirmed tickets? If their system is unreliable. Why are they using it?

See news article below:

https://www.gmanetwork.com/news/mone...-glitch/story/