what do you do when you don't receive the call from a stranger?

Well, luckily for me, at the moment, until now I have not ever receive calls from unknown persons. With the exception of call-center operators that do nothing but bother me, trying to get me to make a deal (for them), but I'm ready to throw down the communication at once. However, in the event that happen to receive phone calls from a stranger (I hope it never happens!), I would first like to know who he is and what he wants. If he persists then the bother, then, would take action the police, maybe putting my receiver under control.

If you are not interested in taking a call from a stranger, then it is alright. You are just keeping yourself safe from any untoward incident that may happen.