I have been getting calls from the same prefix for weeks. 718 245 or 246. Every week these idiots seem to change the last four digits. I have to keep updating my call blocker. I don't hear them after I block them but will see the history should I check my phone. At least one call back to another number (using a company conference room phone with CID blocked) I got a "Magic Jack Customer's VM is full.: So I believe these are Magic Jack numbers being hijacked.
I suspect that the aggressiveness of these calls is programmed to develop a database of target's answering habits - and further suspect that this is being done in preparation for political calls as election time approaches. Could just be a criminal survey too but the local areas code makes me think more political.