Check out their t&c that every purchaser agrees to before buying:
15.1.1 Without prejudice to any applicable passenger rights pursuant to any international or domestic laws, times shown in timetables, schedules or elsewhere are not guaranteed and form no part of the contract of carriage
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No airline guarantees their schedule, for good reason. Any expectation that airlines' schedule are anything more than their educated guess is folly.
Now, they handled this situation very badly, and I hope they have learned from their experience.