I seriously doubt the post office had much to do with tracking him down. My repeated experience with the USPS is that they pay absolutely no attention to mail forwarding requests, ever. It's far more likely that someone at the matching network did some googling.

And I don't need a new phone number, that's kind of the point. I can switch providers and still keep my number. I can move to the other side of the country and keep my number. That's what I want out of the post office.