I was rejected twice from two MSc programs, should I quit trying?
If this is necessary for your career, certainly don't quit trying yet. But realize a few things:


Being at a top school doesn't always matter much for graduate studies, especially in Canada where Masters programsv tend to be more like mini PhDs. So you may find you have more success applying to smaller schools where there is a supervisor whose interests match your own. The supervisor likely matters more than the school.
Strengthen your application in any ways you can. Take some time to get experience in your field outside of academia. Do some extracurricular activities that show leadership potential. If you can upgrade your marks, do so. See if you can turn your bachelor's thesis into a published paper.
Put lots of effort into the other aspects of your application. Make sure you have excellent references. If there's a place to explain extenuating circumstantial, use it to explain your GPA