In a world where online fraud is sadly booming, most people realise the importance of checking their bank and credit card statements to make sure that they have not become a victim.
But how many realise that their supermarket rewards schemes can even be targeted by thieves?
Check your account
More than 15 million Tesco Clubcard users are being urged to check their statements after a security breach was revealed.
Thieves have managed to log on to Clubcard accounts and print off vouchers, which they have then been able to spend in Tesco stores without having to show identification.
According to the Telegraph, some customers have even been targeted more than once and one person has lost more than £400.
This sum is potentially worth even more to the criminals as the supermarket is offering to double the value of the vouchers when paying for certain products.
The fraud was originally noticed at the beginning of 2013 but the Telegraph and other financial experts believe that customers are still becoming victims.
The newspaper said that it had been contacted by customers targeted in December 2013.
The MoneySavingExpert website also claims to have been contacted more recently than the beginning of 2012.
According to Choose.net and other websites, 2,240 stolen email address and passwords for Clubcard accounts have even been posted online. The information is said to include the value of the accounts’ vouchers, which totals £64,288.50.
Tesco said that it had suspended the affected accounts and contacted the relevant customers. It has vowed that it will ensure people do not lose out because of the fraud.
What can you do to protect yourself?
Make sure you check your account regularly and change your Clubcard password immediately. If you use the same one for other log-ins, change those too.
Tesco has said that the fraud is not a result of their systems being hacked but has been made possible by people using the same password and email combinations on various websites as they do for their Clubcard accounts.
Customers, however, have told the Telegraph that their passwords were unique, but changing yours is still the safest option.
When checking your account activity, also check your personal details as some people have reported having their registered names changed, and some have even been unable to access their accounts.
What to do if you are targeted?
Tesco has already re-issued some vouchers that have been stolen automatically, but if you have not been contacted, get in touch.
The supermarket has promised to give victims back their vouchers as soon as possible after it has been made aware of the fraud.
Do not be embarrassed or afraid to contact the supermarket if you have been a victim, and do expect to get your money back.
If you apply recommendations in the Lending Code, which sets out voluntary guidelines for financial institutions to follow, Tesco must prove that you are being dishonest or that you were negligent when it came to handling your log-in details in order to have a case for refusing you a refund.
If you suspect that you have fallen victim, you should contact police through the Action Fraud website or by calling 0300 1232040.
Action Fraud has been set up as a national centre for reporting internet crime and fraud.
People who contact the centre can be put in touch with the Victim Support charity, which can offer everything from emotional help to practical advice. Concerned people can also contact Clubcard customer services on 0800 591688.