The limits of communication

My phone rings. I don't recognise the number. It might be a potential client so I answer.
"Hello, Julia Sandford-Cooke."

"Is that Stuart?" asks a man.

"No," I say. "I think you've got the wrong number."

"Is Stuart there?" asks the man.

"I don't know any Stuarts," I say, "You must have the wrong number."

Slight pause. "Is Richenda around?"

"You have the wrong number."

Slight pause. "Is this 078XXXXXX?"

"No," I say, "You've definitely got the wrong number. Try again."

Slight pause. "I must have the wrong number. Sorry."

We hang up.

No matter how many times you tell them, some people just have to work it out for themselves.