dont know who it was cuz I didnt answer.  they called on my cell & did not leave a message

This number calls my cell phone several times per week, and has been doing so for the past few months now. I'm on the East coast, so it's generally late evening. I don't answer now that I know it's some sort of telemarketing, but these phone calls are getting ridiculous! I'm on the do-not-call registry so I'm unsure what to do to get them to quit.

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:  fccinfo@fcc.gov

they have called several times but hang up after several rings

Horizon Solar Power Telemarketer!!