They are so overfamiliar that I sort of join in.
"Oh hello, I didn't catch your nname"
"John, ma'am, how are you?"
"John, I don't know a John"
"How are you ma'am?"
"I'm sorry, where did you sy we met"
"I'm john, how are you ma'am?"
"Ikm awfully sorry but I don't usually take calls from people I haven't met. Where did we meet?"
"It's john ma'am, how are you?"
Who gave you my number please?
..... Silence
We are registered with the TPS service. Can you tell me were you got my number from?
..... And then the line goes dead.
Do drop it OP. At least cut to the chas and don't waste people's time.