Updated: Nov 6, 2020
Recently, you may have received an urgent-sounding voicemail from “Apple,” claiming your “financial activity” on your devices was at risk.
Don’t worry. Apple isn’t calling users to personally warn them about supposed suspicious activity. This is a spoofing scam in which scammers mimic Apple and are trying to get your personal information.
Apple will never ask you for your personal information nor will the call you out of the blue. If you did not make the call, just ignore it.
I have also posted an article from Apple explaining how to detect junk calls.