Charities, along with some Survey's and Political calls, are exempt from the DNC, however, they can still get into trouble for not placing you on a internal DNC when asked, you can also check your states laws in regards.  Some states have different laws in regards to the calls,  which can differ from the federal.

http://www.ncdoj.gov/News-and-Alerts/Alerts/Don-t-fall-for-fake-surveys.aspx
http://www.komando.com/columns/264108/3-thing ... call-registry-2

http://www.tcpalaw.com/
http://www.kleinmoynihan.com/publication/new- ... ctober-16-2013/
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://business.ftc.gov/documents/bus27-compl ... -rule#DNCrights

Do consider maybe getting a call blocking device or phone.. You can google them and many are around $40.00 or less. 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.

Report your callers here if they continue to call and harass:

https://www.ftccomplaintassistant.gov/#&panel1-1
https://esupport.fcc.gov/ccmsforms/form1088.action

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