Credit Card Fraud
I reckon this should be possible...

* Send someone the following SMS from an anonymous number.
* "Your Barclay's credit card (starting 4304) was recently used to buy £2,103.54 worth of goods in China. If you wish to dispute this transaction, please call 0113 496 0123."
* The victim checks her BarclayCard - it does start 4304. Damn! She rings the number.
* "Welcome to the BarclayCard fraud line," says the voice at the other end.
* "To protect your security, please type in your sixteen digit card number," says the automated voice. So that's what the victim does.
* ... after typing in several more details ...
* "Unfortunately," the voice says, "the £2,103.54 will show up on your July statement. But you will see the refund on the August statement."

Remember - the first part of your credit card number is fairly predictable.

Credit card fraud is illegal. Do not try this at home.
(terryeden, Tue 10 Jul 2012, 12:32, 9 replies)

I've fleshed this out in a bit more detail on my blog
(terryeden, Tue 10 Jul 2012, 12:33, closed)

The Co-Op Bank are wankers
Every so often I get an automatic phone call from the co-op bank. In order to identify myself, it says, I must enter my card number, the expiry date, two digits from my PIN and my date of birth.

Every time I enter gibberish and then ring the bank myself. Yes, they say, their automatic system has been trying to call me. They seem utterly baffled at the idea that training people to enter card and security details in response to unsolicited calls might possibly, just possibly, be a bad idea.
(ubergeekian, Tue 10 Jul 2012, 12:53, closed)

I used to work for Lloyds TSB and they did exactly the same thing.
AFAIK all the major banks do. Utter idiocy, yes.
( Zuowan, Tue 10 Jul 2012, 13:04, closed)

It's not like they actually take any notice anyway.
Having entered all this crap, the first thing they'll ask you for is exactly the same info again.
(username failed moderation, Tue 10 Jul 2012, 13:07, closed)

I got into a Mexican stand-off with Lloyds for about a month
They wouldn't tell me why they were calling without me answering their security questions and wouldn't give me a number I could check to call them back on.

If I called the usual telephone banking line there was no note on my account. In the end I made them write me a letter.
( Ghoti Fingers, Tue 10 Jul 2012, 20:19, closed)

Nationwide are worse
To verify your identity, please select the month of your birth.
If you were born in April, press 1
If you were born in March, press 2
If you were born in May, press 3

*2*

I'm sorry, that is an incorrect answer.
If you were born in April, press 1
If you were born in March, press 2
If you were born in May, press 3
( Ungersven would support SpankyHanky's patreon, Tue 10 Jul 2012, 13:35, closed)

T-Mobile do it if I forgot to pay my bill, too
But they use real people, so I got them to put a note on my account that I will only give them the security details if they recite a certain nursery rhyme. Not saying which, obviously.
( Ungersven would support SpankyHanky's patreon, Tue 10 Jul 2012, 13:36, closed)

My bank stopped calling me...
I insist on going through security procedures when ever any financial institution calls me; most have stopped though one credit card vendor has now rolled out one of the tactics I insisted on (I provide letters in postcode they provide the numbers)
( notmyrealname, Tue 10 Jul 2012, 22:17, closed)

Stopped 3 'customer care' dead
Did the same - except I've never told them the password either. They stopped ringing me _every_ damn week.
(baldybeardy, Wed 11 Jul 2012, 22:31, closed)