Having fun with telemarketers is fun, but the OP had someone actually want to visit the house. Weird. Maybe they were going to show up with a "prize" of a $10 off carpet cleaning deal or something.

Next time tell them, "Sorry - we can't have visitors because we suspect my dog has rabies....we're waiting on the results to come in. But we can come to your office to pick it up. Where is it?"