Google your name and number, any place such as spokeo that shows up, make them remove it.  You might be surprised what comes up. There are web sites out there with your info on them and right down to relatives. As a rule, the illegal callers just plumb in a set of numbers to dialers or computers.

http://800notes.com/forum/ta-9b593c6d671798c/ ... sed-to-scammers
http://800notes.com/forum/ta-c5016ae94e29b44/ ... oyment-benefits
http://krebsonsecurity.com/2014/04/u-s-states ... ch-at-experian/
http://800notes.com/forum/ta-a55d53405a192ce/ ... alware-campaign
http://www.nytimes.com/2014/08/06/technology/ ... tials.html?_r=1

Do consider getting a call blocking device or phone.. You can google them and many are around $40.00 or so.If its a cell phone, some already have call blocking, if not, there are free apps on the web that will work for some. You can google this. If you have a smart phone, there is a free app called call control. Iphones appear to have apps also. Another one is called Mr. Number.

As for the DNC, its does as it was intended to and it is enforced.  Legit business's have to purchase it and prove who they are.  Its not a call blocking device or phone though.  And if you tell verizon not to call, it means them and their affiliates (back it in writing sent certified or return receipt USPS mail)  they must abide by it the same as any other company despite being your service provider.

Report your callers here:

https://www.ftccomplaintassistant.gov/#&panel1-1
https://esupport.fcc.gov/ccmsforms/form1088.action
https://complaints.donotcall.gov/complaint/complaintcheck.aspx?panel=2

http://www.stopfraud.gov/report.html
http://www.fraud.org/

And here are the links to read and understand what the DNC's are, what they do and what they do not.

By State DNC lists:
http://800notes.com/res/DoNotCall.aspx

http://www.tcpalaw.com/
http://www.consumer.ftc.gov/articles/0108-national-do-not-call-registry
https://www.donotcall.gov/
http://www.ftc.gov/opa/2008/04/dncfyi.shtm
http://business.ftc.gov/documents/bus27-complying-telemarketing-sales-rule

http://800notes.com/forum/ta-c46b87360deec56/ ... -unwanted-calls
http://800notes.com/forum/ta-c4ffa8334de58ff/georgia-dc-out-of-business

Enforcement:
http://800notes.com/forum/ta-c33b770fc3695c0/ ... -associates-llc
http://800notes.com/forum/ta-c3355f57425c0d5/ ... alls-to-the-fcc
http://800notes.com/forum/ta-c17c24b9614a487/ ... ttery-scam-case
http://800notes.com/forum/ta-c116acd736280bb/ ... h-telemarketing
http://800notes.com/forum/ta-bfcd4eb5e5bf6d6/ ... y-ftc-and-il-ag
http://800notes.com/forum/ta-bf7e49d2ddb0453/ ... e-dnc-violation
http://consumerist.com/2015/04/08/robocalling ... ding-consumers/
http://transition.fcc.gov/eb/
http://www.consumerfinance.gov/blog/category/enforcement/
http://www.ftc.gov/enforcement
http://www.ftc.gov/opa/2013/09/ambrosia.shtm
http://www.ftc.gov/os/caselist/1223190/
http://www.consumerfinance.gov/newsroom/