What happens when a call is blocked on a landline? Follow When we block a call we give them a "message" saying Nomorobo has blocked the call. If the caller enters the Captcha code, we push the call through to you. If not, the call is terminated. Related articles Can I see a history of blocked robocalls? How does it know which calls to block? How does it work on Landlines? Getting calls from 608-371-6666? What is my Nomorobo Number?