Re: Solution at the end user, er..., end
I use this on a Raspberry Pi:
It has blacklists and whitelists, which can include regular expressions. For blacklisted calls it can play a recording or emulate a fax machine. Best of all, in the UK it will seize the call before the first ring, so you are never interrupted by the spammers. It's a simple matter to parse the log file to create a web report.
(No connection other than as a user).