Agree to buy whatever they are selling but when you give them your card number don't read out the last digit. Act dumb and pretend you have a card wth 15 digits.
There's only 10 combinations until they find the right digit though...
no you don't.
I'm 52 and with both phone and door callers I just say "Me Mum & Dad aren't in".
I normally get a funny look at the door but so what.
"Can I speak to the House Owner please?"
"No he's out of the country"
Burgled next week then.
I just got a call from an aussie bloke saying "I'm trying to raise awareness of the RSPB"