How can I stop spam calls from 8XX numbers?

If you have an iPhone, try Silence Unknown Callers. The calls won't ring, though they can still go to voicemail. Check the call log and voicemail periodically so you don't miss anything legitimate.

Android phones may have similar call screening or spam protection settings, but the options vary by phone.

Check whether your phone or carrier offers spam call filtering. Some calls may already be labeled as suspected spam. A call filtering app is another option if the built-in settings aren't enough.

Some call blockers can filter numbers by prefix, which may help when each call comes from a different number. Be careful about blocking every number starting with 8, though. That could also catch calls you want to receive.

You can also let unknown calls ring through to voicemail rather than interacting with the automated message. That won't guarantee the calls stop, and it won't solve the voicemail clutter, but you can delete the messages without engaging.