On a land line, your best defense for this stuff is an answering machine with a ring limit of 4 before it kicks in.  If no message is left, put the number into your blocked list.  Panasonic has an excellent phone system with call block.  On an android cell phone, check out the
Mr Number app.

4/7/16 1213 & 1308 did not answer, no message.

robo call "This is Bridgette from Card Services....." I keep blocking their calls but they come up with NUMEROUS other phone numbers to call from!!!  I have blocked at least 10 different numbers with this same message from either Bridgette or Rachel.  It is driving me crazy.  There IS such a thing as "Card Services" and I personally contacted them to see if they were calling people.  They are NOT.  This is a horrible, annoying, persistent couple of ladies!!!

If yours is a newer call blocker, you can block via the area code. In a lot of cases, they tend to use the same area code ad nauseam. There is more then one scam operation out there using this also.

Report your callers here, not just to the DNC alone:
Federal:
https://www.ftccomplaintassistant.gov/#&panel1-1
https://consumercomplaints.fcc.gov/hc/en-us
https://complaints.donotcall.gov/complaint/complaintcheck.aspx?panel=2

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

FCC Abandoned Calls Complaint form:
http://www.fcc.gov/cgb/consumerfacts/1088D-R.pdf
email:  fccinfo@fcc.gov

Called mobile, did not answer, no message left (this time). Has been a female voice that sounded like she was in a can, saying some garbled spill about student loans, and to press 1 to talk to a live person (on voice mail?) Then when you call back (from a different number), a rude jerk of a guy asking if I liked pizza...