They use dialers or computers and just robo call blocks of numbers. Illegal telemarketers like this don't care if your on the DNC list, nor do they care what type of phone they call or if its unlisted or not.
Consider getting a call blocking device or phone.. You can google them and many are around $50.00 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.
Report your callers here, not just to the DNC alone:
https://www.ftccomplaintassistant.gov/#&panel1-1
https://esupport.fcc.gov/ccmsforms/form1088.action
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:
[email protected]