You should be able to set your cell phone ..... where you can reject a call anytime you don't recognize the # ... you will not be charged for the call if you don't answer. Your provider should be able to show you how.
Got a call from 310-340-7333 which is a bogus number. I hung up after playing them the message you get when calling that number. They called back from a live number which was (818)340-7333 from a company called NRG. Maybe we should call them and find out why they like calling from bogus numbers.