As someone who hates phone calls in the first place, Google Voice has been a boon to my workflow. Calls go in and I rarely, if ever, check them. It’s truly a marvelous invention.
However, Google Voice now has global spam filtering that allows you to report spam callers and block them. GV always had a blocking system. However, now the data you add to Google Voice percolates out to other users, thereby saving them from your sad fate.
To enable the feature, pop over to the Call tab of GV settings and select the proper checkbox.
Spam calls appear in the Spam folder and can be heard or, if you’re in a malicious mood, deleted.