Block "No Caller ID" calls on iPhone 6S
I need to see if there is a way to block calls with No Caller ID coming to my iPhone. Somehow my iPhone number got into the hands of spammers telling me I was given a grant by the Feds. Of course it's not true, because the Federal Government doesn't call you, but regardless I would like to block these calls.
I cannot find an app' to do it without cost and now would not be a good time to change my phone number.
iPhone 6s, iOS 10.3, Block Unique Phone Calls