One simple thing you can do to stop unwanted callers with FreePBX is install the “Blacklist” module. Obviously this will only work if the Caller ID number is presented to your system when the caller rings.
To install the module click on the Tools tab in FreePBX and then the Module Admin menu option. Then click “Check for updates online” and you should see all the available modules. Select the “Blacklist” module and select “Download and install”
Then scroll down and click “Process”
Next, click on the new “Blacklist” menu option on the left and enter the number to be blacklisted. Make sure you enter the number in the format that it is being presented to your system. Check your call log reports for what this is.
The caller should now get a message saying “The number you have dialled is not in service”