Land line telephone info

I'm trying to access a feature in myatt account which will allow me to delete the blocked phone numbers to free up more space. I have been flooded with robo calls with no one on the other line. It is now full and will not let me add anymore.

Any attempt to access my phone account results in being sent to my direct tv info. This is extremely aggregating to the extent we are considering cutting the cord on both services.

Please let me know how to access the phone account ONLY!!!!