On Line Phone Tools - Blocking

I just found the On Line Phone Tools.  How do I block calls from this screen?  I am sick and tired of the robocalls I get.  Do not call does not work - I have been signed up for years.  The robo calls are so bad my cox line is absolutely worthless - I only plug it in when I am making a call - and some times the robo call gets through before I dial the number.

Why can I not "check a box" to block a number on the On Line Phone Tools?  I pay for the cox phone service.  Right now the phone service is being abused by the robo callers.

How do I get a cox number where all the callers pay a fee?