When I get these types of calls from unfamiliar area codes I let it ring until it's done then block them. If it's a local area code and I answer it I just say f#$k you repeatedly until the recording is done, and I don't seem to get calls for at least two months. My theory is that the calls are being recorded and phone numbers are shared or sold so if I act like a psycho they won't waste their time with me. If they want to call the cops I say bring it on because my phone records show that they called me and I never call them (if you could even get through) so screw them.