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, 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

Another call from a number different from the last one, but again saying that they are Credit Card Services and that they represent over 500 banks that issue credit cards. They say they can help me lower all my interest rates. I asked them to stop calling me, and added their number to the ones I block.

Thank-you for the information.  I was wondering what call blocker you use.  I am so tired of all these unwanted phone calls and I feel these people are hijacking my phones.  Once again, they have all the rights and the victims have none!

The very old credit card "services" scam.  Reported, again.  And blocked.  But the number changes every time, so blocking is pointless.  

Hang up, no message. I use NQ Call Blocker but they have to call once to add them to the list and it appears they change constantly.