Another free phone number app for iOS is textPlus. It works well for toll-free numbers. (You can get free minutes watching ads to call non-toll free numbers.)
They have a soundboard called “EmojiTones” which include sounds like a toilet flush or “I love you” or fart. So even if you don’t want to talk to scammers you can play sounds until they get frustrated.
It’s worth having as a backup for baiting.