Just got a call from this number on my cellphone. Woman greeted me with "buenos tardes" and then asked in English if I spoke Spanish. When I asked who was calling, she hung up. Obviously, FTC do-call-registry is totally useless.

Dear Aggravated  ,

The DNC works just fine. It is for telemarketers only and honest business does indeed abide by it. It is the criminals (which includes illegal telemarketers), frauds and scammers that do not. However, the Fed. DNC does not cover some survey's, Political or Charities.  You would need to check your states DNC laws to see if these are under your states DNC laws.  The fact remains that they are not automatic call blockers though and can not protect you from the calls that are criminal, illegal or fraudulent.

Do consider maybe getting a call blocking device or phone.. You can google them and many are around $60.00 or so.

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://business.ftc.gov/documents/bus27-compl ... -rule#DNCrights