We had the BT one this morning when DH and I were in the middle of a very important conversation, I'm afraid he told them to S.. off! When he calmed down he checked the number so he could report it to the TPS but it was an 00 number so no point.
I have previously posted about a friend who can put on a very strong, rather dim, Norfolk accent. He kept a conservatory salesman on the phone for a very long time, even made an appointment for him to come round to quote and then, just before the end of the conversation asked if he needed permission from the man in the ground floor flat to do it! He doesn't even live in a flat but is a surveyor so was able to think of lots of good questions.
If I'm but I just tell them, in my most apologetic voice, that the lady of the house doesn't take sales calls. It usually throws them as they think I'm the housekeeper or secretary.