(Would help to turn off the all caps.) IRCC will on occasion telephone applicants or candidates. So this may be legitimate. But it might not be legitimate. (Unfortunately there are scammers whose agenda is little more than mischief; while there have not been a lot of reports of phony IRCC calls lately, there have been times in the past during which there was quite a lot of this.) Thus, I would be sure, absolutely sure, to verify that you are no longer scheduled for the oath. That is, make sure to verify that this was indeed a legitimate call from IRCC. At the least call the IRCC help centre, which can require a concerted effort to get through, and be sure the call centre representative checks your personal records to verify whether you are scheduled for the oath or not. If there is any doubt at all, SHOW UP for the oath. You do not want to miss a scheduled oath even if you have a very good reason. All that said, it is possible that the call was legitimate and that IRCC scheduled oath ceremonies in anticipation of timely receiving clearances, but for whatever reason the clearances are not yet available. There are some indications that IRCC has been rushing to complete applications this year, perhaps in anticipation of the rush of new applications when the new rules take effect, so this sort of mix-up would not be surprising. Nonetheless, best to absolutely verify the call was legitimate and if there is any doubt, best to show up just in case.