The press-9 hang-up trick is a solid first layer .. good thinking. For rotating numbers though, that alone won't cut it since spammers cycle through constantly. On the 3rd party side, the most common approach people implement is routing inbound calls through Twilio first before they hit Vapi, then using Twilio's built-in spam scoring (their "Verify" or "Voice Insights" add-ons) to reject flagged calls upstream. Some also use tools like Nomorobo or Hiya via webhook before the call connects.