I use an app called Should I Answer? It uses crowd sourcing to collect robocalling numbers. My phone doesn't even ring for most of the robocalls now, and the ones it misses, I can add to their database so others won't get them.
How does the database work, when it’s just your own number with the last two digits different?
I've literally been robocalled from my own number before. I don't think this would work
Depends on the carrier. Proper equipment should be like “WTF? This is obviously spoofed” and reject the call but then again the entire telco industry is fucked up.
back in the 2000s, you used to be able to get into most peoples' voicemail by calling someone's phone with it's spoofed number. Lots of people didn't use voicemail passwords.