I got this reply from NGF office this morning
Good Day
We are currently in the process of rescheduling everyone that has unfortunately missed their Oath of Citizenship Ceremony due to the strike action and knowing that many people all have circumstances to deal with. You should receive your Notice to Appear in due course as we are focusing on those individuals first.
Please monitor your e-mails, and junk folder as well as sometimes they do end up in there
Regards,
Citizenship Official
IRCC Citizenship Program
Niagara Falls