Get the caller to admit he got the wrong number

A friend from college usually answers to phone with a bogus greeting whenever he gets called, since most of his calls are from unknown numbers. I've been meaning to try it out, and got the perfect chance to do so yesterday.

Some unknown number calls my phone. I pick up and clearly don't recognize the caller's voice. He was looking for a "Christopher"; I couldn't hear clearly.

"Cambridge animal control, how may I help you?" I responded.

"Sorry, who is this?" He sounded surprised.

"Cambridge animal control." I reiterated.

"Oh sorry, I got the wrong number." *click*

Success!