I've been getting these call for several years.
This what I've found to be pretty effective.
I made a list of spam callers phone numbers and when one of them call, I answer with
AN INDIAN ACCENT AND SAY HELLO, HELLO, HELLO, AND I DO NOT IN GAGE IN CONVERSATION WITH THEM. This drives them crazy and they hang up.
Mission accomplished! Then they put me on their DO NOT CALL LIST. !!!! I win.  

Now, those call have dropped off a lot.
It works for me, Try it You'll like the results.
9/6/13

Ditto to all the above.  This number calls me at least twice per week.  i've reported it to FCC and amm saving all the missed calls and voicemails for proof.

This phone number calls me at least 3 times a week.  Its touts lower car insurance rates.  I have called them back, left a message & told them to stop calling.  I have also reported them to the FCC.  But they continue to call.  I am on the DNC list

I have received several calls from this number.  Once a woman answered and when she heard my voice, she hanged up.  I believe they are trying to find elderly people, or people they can take advantage of by getting their info.  If they sense that you are strong willed, they let go of the call.

Jordan has been asked 4 times to remove my number. Now she's screening her calls so that I can't complain more.  I'm on the national do not call list and have filed a complaint with the FTC.  Next, I'll be contacting all of my friends on social media asking them to call the number and tie up their lines.

They continually call and it's only a recording for some s****y insurance company.  Once I called back, "Jordan" answers the phone and hangs up once you ask who was calling.  I called back from my house phone and surprisingly they answered the phone.  I told "Jordan" to stop harassing me and she asked for my phone number to put me on the "do not call" list.  We'll see what happens now.

They've called me 5 times! STOP!

This number keeps calling me about Car insurance crap

This number called and I let it go to voicemail. They didn't leave a message so I called back. Someone named Jordan answered and told me that they had some NEW CAR INSURANCE RATES ugh. I said I wasn't interested, but she hung up the phone before I could tell her never to call me again. Don't waste your time with this number

This caller keeps calling my cell I don't answer either

they keep calling my cell - i dont pick up

Number has also harassed me.

This number keeps calling on my home phone and cell