The "automatic call block" works by checking incoming calls and asking the caller to enter an access code before it rings. Since incoming automatic calls are unable to enter the code, the device detects automatic or promotional calls and does not ring.
Can you block calls only from someone?
**Block calls from specific numbers:
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Open the Phone app. Tap the More button. Enter the Blocked tab and choose the Settings icon. Now enter the Blocklist menu and choose the Plus icon to add phone numbers you wish to block.