[header] How to block robocalls [title] Don't accept the call. [step] First of all, if you're getting a call from an unknown number that you suspect may be an automated message, don't answer it. Though these calls are dispatched via computer, there are often attendants on the other end checking to see whether the calls went through. 
If they know that the calls are being answered, it will just make them more persistent. [substeps] You can usually tell a robocall from a normal unknown number by looking for lengthy or unfamiliar extensions.