does everyone know about the visa/mcard scam? dont give your details to people over the phone, take their number and call them back

Is that specific to some new scam, or just a general hint?

i was emailed details but it went on forever. they call you up and already know your name and address. they say their name and badge no. and that they are from fraud dept. They tell you, £497.99 has been put on your card and thats its an unusal purchase, did you buy it etc...
obv you say no and they ask you for 3 numbers on back of card. blah blah blah, they give you a fake 0800 no to call if any probs, they then call you back 20min later and say on your next bill the £497.99 will be off

That's quite cunning, cos of course once they get the card number together with that code from the signature strip they can order virtually anything. Maybe a good thing I'm v v cautious with things like that and never give out that kind of info until I'm 100% sure I know where it's going.