To report a robocall on your land line, use the Report A Number feature in your Nomorobo account.
There are two options: A Robocall That Wasn't Blocked or A Valid Number That Was Blocked Incorrectly
Fill in the form with any information you have, and then click Send This Report
If you are trying to report an unusual robocall with more than or less than 10 digits, fill in the form with all zeros, and then write the number you have in the "Anything Else" section.