I dont answer calls from unknown numbers. If they leave a message, they're likely more legit than if they don't. If no voicemail is left, ignored and blocked.
Bank survey Scam phishing for personal information, they say it's a followup on your recent bank visit. I haven't visited my bank in Months. I also received an email saying the same thing so I called my bank and was told they were not doing a survey and did not have anyone doing so on their behalf.