Check cabinets, attic, basement, look on top of things. Maybe even take a hammer in case it got buried in the wall like a splitter! That's one thing my heart heart goes out to cable installers for, where you commonly can't find both ends of a wire.

BTW you're a great sport about this whole thing. I'd feel the same especially if they did a good job. Keep looking there's a scaler there somewhere, you'll find it.