okay just to report back.
I filled in the form provided on their COVID page, having little hopes, on Mar 21st. I explained the situation and still believe the same: yes, the flights are flying, but traveling literally 2 days before the border shut down is virtually impossible, not to mention visa situation once we get back. Also I simply wanted a voucher, not a refund, when people flying literally 24 hours after us could have got it with no questions asked is just plain ridiculous. I completely understand that I had no legal grounds for asking for anything, but the options given by FI is so inconsistent and inhumane that I urged them to give me at least an explanation, if not a voucher.
2 weeks later someone at CS emailed me and apologized for the inconvenience, and said they had cancelled the tax refund and decided to issue both me and my mother vouchers.
another week later, emails came in saying that they were being processed.
yesterday another email came in saying that the voucher application was open, I just had to click on the link to claim it. The webpage says the voucher applciation submission successful.

There is no denying FI did not do anything legally wrong initially for refusing everything. But compared to their competitors, their policies were extremely unreasonable, especially for people flying before Mar 20, who were incidentally impacted the most severely. I think in this case of extremely rapid border changes, offering vouchers is the way to go, as refunds may not be realistically possible. However, I have to give FI CS credit where it is due. I am glad that I finally was able to get a voucher and thank them for actually listening to customer feedback. I will continue to support FI after using this voucher, even though it took a few hours out of my life in this crisis.