My locked iPhone 5 was lost. How did this person contact me?

I lost my iPhone 5 a couple weeks ago. The phone was locked with a password, and it had no data because it wasn't with a phone company. I thought about contacting an Apple store and blacklisting the phone, but I figured it's Christmas so i'll suppose my lost as a gift of giving.

Ironically, I received a phone call from a pleasant voice who told me that the he purchased a phone off of Kijiji (it's like craigslist) for $300, but he found out it's stolen and was contacting the home number to return it.

I'm pleased and ecstatic about the discovery, but my question is:

**how was he able to contact me when my phone was locked?**

I mean, the only way to get into the phone is with a password. Unless he somehow guessed the 4 digit code right (which I don't really see happening), the only way to use the phone is to reset it, and that would wipe out everything on the phone.

Probably the same way he found out it was stolen. The EIN was registered to you at some point, and a helpful but misguided employee provided the contact information. The info is supposed to be private, which is why I say misguided.

Or, perhaps you had a sticker on it or case with ID info