When receiving an unsolicited call I have found the absolute best response it to quickly, politely cut the person off and say “I’m sorry, this is a mobile phone, please remove it from your list.” (yes, even if it is a land-line)
They are surprisingly courteous and willing to get off the phone quickly in this situation. I believe there is some kind of rule about calling mobile phones since the customer is paying for inbound calls.
I learned this after I had forwarded my home phone to my mobile and was receiving telemarketing calls on it.
(sorry about the following extraneous finger photos, but I was google-imaging for a middle finger and I just couldn’t pass these up)
1) Extend either arm at an approximately 90° angle perpendicular to the body.
2) Bend arm at the elbow. Position it parallel to the body, forming three sides of a perfect square.
3) Close palm tightly.
4) Fiercely upturn digit between pointer and ring finger.
5) Hold approximately 10 seconds to a minute for emphasis.