Spam Calls grown exponentially after voter list information made public

I discovered a setting on my phone app that any unsaved phone number that calls it asks the caller for more information before the phone rings. I am now getting at least 3 spam calls a day and the phone screens them out. It still shows in calls received but no ringing.It's on my iphone - settings, apps, phone........ Ask Reason for Calling - Calls from unsaved numbers will be asked for more information before Iphone rings. Calling and data rates may apply.