Manage blocked list/blocked contacts on the Phone app

1. Go to Settings-> Phone->Call Blocking & Identification to see or manage the contacts and phone numbers you've blacklisted. From the Settings menu, you can also add new Block Contacts and Edit or Unblock numbers.
   
   
    unblock calls/contacts on your iPhone 8 Plus
   Follow these procedures if you change your mind and want to unblock contact from your blocked list:
   1. From the Home screen, choose Settings.
   2. To use the app, tap Phone.
   3. Select Call Blocking & Identification from the drop-down menu.
   4. Choose Edit.
   5. To confirm the action, tap the Unblock option.