That ad reminded me of a scene from the Goon Show which went something like this:
[Knock, knock...Sound of door opening.]
"Yes, what is it?"
"Hello, Mrs, we're from BT and we've come to disconnect your telephone."
"But I don't have a telephone for you to disconnect!"
"Not to worry, Mrs, we've brought one with us."
"Oh, in that case, you'd better come right in and disconnect it then."
Would it have bee Minnie who opened the door? It was so long ago that I heard it...Absolutely amazing how something like this post can evoke memories from more than 60 years ago!