I have two VOIP lines at home and would have no issue with putting a packet sniffer upstream of the cable modem. What I want to know is how to identify the servers generating the VOIP calls with the spoofed caller ID's. I'm in a position to take legal action. I am aware that the people I may be dealing with could be located in Russia and the former Soviet client states that Brian Krebs writes about in SPAM Nation. I am also aware that a good number of these callers are U.S. Generated political hate speech designed to disrupt elections. I am located in SOCAL (near Steve Gibson) and I would like nothing better than to see just how far I can go to track down and then sue these generators of false Caller ID VOIP "SPIT"
Seem's like your phone number must have gotten tossed around in the sea of web and got into the hands of some Russians or what.
If they are harassing you then you have every right to call your local police department, give them all the information that they need and they should be able to make a trace on the call and or help you to block the caller from contacting you.
You can also contact your call provider and see if you can possibly change your phone number or have them forward you the logs and / or try and block the caller /s from calling you again.