I am getting these calls every day too, and I am ready to blow a gasket. Every single day and sometimes more than once. They are contractors, Go Green, California Energy Initiative, solar energy sales people, etc. They have number like: 309-1042, 818-164-7558, 818-148-6792 and the list goes on and on. Who is selling our numbers that are supposed to be on the "Do not call list"? These people are rude and annoying, and hang up when you ask them for a phone number to call back or their contractor number.
Didn't have a number but, caught him out when he said he was with "California Energy Initiative". Toyed with him a little bit, until I lowered the boom. Pissed him off so badly that he tried calling back three times. I asked him why he hated his life so much that he had to work for a telemarketer. That hit a nerve.
Regarding "selling numbers" Most of these scammers use VOIP systems for cheap calls, and use property lists (or, in my case, 20-year-old lists) that they are sold by some other company promising "live leads." If you're on the Do Not Call list, FILE A COMPLAINT at https://complaints.donotcall.gov/complaint/complaintcheck.aspx
It builds a pattern that can be used to track these goobers down.