Home Voice Call Block / SPAM Filter feature not working as advertised

I've been on calls with Xfinity advanced tech, who reviewed my settings and confirmed everything is set properly to filter spoofed robocalls. We continue to receive calls that show things like "Not Available" (with number, various city/location/company names (with number) - including one that showed "COMCAST" shortly after getting off the call that confirmed that calls like that should not come in. I check these calls by calling the number shown back and get either number disconnect, number invalid, application error, etc. So the robocallers are using some list of numbers that maybe were valid at one time but no longer are. Why aren't these calls that are originating from numbers other than what is displayed on caller ID being blocked? Adding them to blocked numbers is pointless because the numbers change. I even tried to escalate this issue via phone support and they insisted on sending a tech out to verify connection / hardware / etc. even though the cable modem had NOTHING to do with the call filter/spam block feature (it's all cloud and/or Xfinity backend infrastructure based). The onsite tech verified everything was functioning properly from a hardware / connection POV.

For the record, my settings have anonymous callers blocked, and my High and Medium risk calls are set to block, and Low risk is set to send to voicemail.

Please fix this....