Who called from 7206085687

I get calls at all hours from this number.  I have called ID so do not pick up.  I am on the "do not call list" and find this very annoying.

I get at least 3 calls per day, 7 days a week from 720-608-5687 from Georgetown, Colorado. They never leave a message. How do I get them to stop calling ? I am on the do not call list.

I get calls multiple times a day and even at night when I'm sleeping from this number. How do I block this number?

Finally gave in and answered, even though I normally don't if I don't know the number.  Turned out to be Sirius satellite radio trying to sell me a subscription.  I just bought a new car that came with a trial of it and the trial is up.  I asked her to just mail me the info but she persisted with the hard sell.  I never used the satellite radio during the trial so I told her I wasn't interested and hung up.

I also told them I wasn't interested in Sirius radio but they keep calling.