Credit card companies have already solved this problem by publishing a well-known 1-800 number that their customers can call back to verify the intent of an unexpected caller.
Google Duplex can do the same thing - without even staffing a call center.
If you get a call from someone who claims to work at the credit card company you use, instead of trusting the caller (who could be a scammer) and potentially divulging private information, you should just hang up and call the number on the back of your card.
Google Duplex can do the same thing - without even staffing a call center.