This could be a case of a bank error, fraud or identity theft (see question Q506 for further information about identity theft).
You should immediately contact your bank/credit card company to report the discrepancies and to terminate your card. The bank/company will have their own fraud department, if necessary, may investigate the matter in conjunction with the police. Take the credit card company/bank's advice on whether they want you to report the matter to the police, as it could just be a mistake, or, they may take on that responsibility, as in some cases they are the actual victim suffering losses, as you are likely to receive your money back.
If you think all of your credit/debit card(s) details could have been compromised you should contact the relevant banks and the credit card companies to stop your cards, as necessary.
If you think you have been the victim of identity theft you should ensure personal and financial information is kept secure, shredded or otherwise destroyed (do not put such material in the bin or take it to the dump/tip.
You should always be aware of information on your computer being accessed and take any appropriate security measures. There are a number of possible security threats you should be aware of -
◾ Someone could pretend to be you;
◾ Your card could be cloned. Be very careful when using cashpoint machines, particularly in public places. Criminals can put a realistic front on the machine which reads your card details, and a video camera photographs your pin number. Opportunist thieves could be looking at you entering your pin number, then snatch the card from you to then go on and use the card. Always cover the pin number entry with your other hand or by some other means if you can.
◾ Someone could use your personal details, obtained by a variety of means to obtain cash or property.
For more information, please see the websites in Related Information.