I can do that too and do, BUT you have to have a phone with that capability.  Some phone providers offers a block number service, but it comes with an added cost on your bill.

These PPL will not stop! I have asked several times for them to stop calling me (I am on the do not call list). They are running me nuts with "lower my credit card". Thanks to Sue on this site I reported them via: https://complaints.donotcall.gov/complaint/complaintcheck.aspx?panel=2  I suggest you do the same.

Caller ID said it was "Servers TDM". It was before 6 a.m., our time! It was a real person, and not a "robo call". The man had a thick Indian accent and told my husband "this is a call to get into your computer." My husband offered him a rude suggestion and hung up!

got robocall on caller ID said 'California' from 213-344-4839 on Thursday 02-14-13 @ 1135AM.
This call message started out with 'This is from CARD SERVICES there is nothing wrong with your account........ So I pressed 1 to be connected to a Live body. The phone call then switched over like I was being connected to a person but then they disconnected me.

This is like the 5th out of the Last 6 SCAM calls that disconnected when I pressed 1, and
unfortunately my "SCAMMER HORN" is starting to accumulate cobwebs.

Robo call from "Kelly" about lowering my credit card rate since I pay my bills on time.   Press 9 to speak to human.    Ahh, the good old "card services" scam people.     Stated they were with Visa and Mastercard, and added Discover later.   Guess "Rachel" and "Heather" got the heave-ho.   It's easy to spoof the caller ID - at least this time it wasn't my own number :).    Received on a land line that's been on the Do Not Call list for years.   Accent was much better with this crew than the usual bunch.