Greg lost his iPhone and wants to know how to use Find My iPhone to locate it. Leo says as long as Find My iPhone is turned on, he should be OK. If it was put it in Airplane Mode, it won't broadcast because the radios are turned off, though. It's probably lost, and even if someone could find it, Greg has a complicated password and it'll wipe the device after 10 attempts.
After he contacted his ISP to get it bricked, he got hacked. Is that related? Leo says that Apple makes it difficult to allow someone who has taken the phone to reset it, but he can't say it's unrelated, he just doesn't know how. Greg should change his passwords immediately and set up two factor authentication. It's likely that they got his account as part of the Yahoo hack and got in that way.