Yes,you have to be very vigilant and careful,and check your accounts on a regular basis.
This is what happened to me in March.
Hi all,We have just had a call from the Halifax asking us to phone a number to check our security details.I was a bit concerned so I phoned the Halifax who informed me it was a genuine number.When i called it I was told there had been some transactions in the early hours of this morning on my card. £678,£339 and £11. All these amounts were declined.My card is at home with me and rarely goes outside.I do use it for online purchases,and this is where it seems someone has got my details,but obviously not the pin number.This is so frightening because I never buy from a site without the gold padlock sign.I have been using the internet for years to buy things without any problems but this has really knocked me for six.