I don't know about Ontario law, so I don't know how much she gets paid. I also understand that the restaurant section was unusually busy for 8:00pm. But that doesn't mean you have an excuse to not do your job. You were given a certain number of tables. If you couldn't handle it, then you shouldn't have taken the job.
I could only hope that woman reads this community. Because I would say this to her: Enjoy the $4. You didn't deserve it.