(215) 415-4010 has called several times recently from PA. Recorded message stating "we have been monitoring your credit card balance for the last 6 months. If you are still carrying a balance of more than $10,000, we can cut that in half and you pay the remaining balance with zero percent interest" or words to that effect. Every time we give out our number, even to seemingly legitimate businesses, we run the risk that our contact information will end up in the hands of scam artists. I agree, unless you recognize the number, it rarely if ever pays to answer.
Just called my number no message. I have had issues with other numbers calling and blocked them so I think once you block them they just get a different number and continue to call. That's ok I will continue to block them.