If you lose your card, it's stolen or you suspect that your card has been used by someone, you must tell us as soon as you can by calling our 24-hour lost and stolen helpline on 0333 123 1812 from the UK or from outside the UK +44 207 201 0526 when calling internationally. We will then cancel your card. Alternatively, you can block your card via the mobile app or on the website.<br><br> We may ask the police to investigate any suspected misuse of your card and they may need more information and assistance from you. We will refund the amount of any transactions which the investigations show are not authorized by you, provided you have kept your card and PIN secure. However, if the investigations show that any disputed transaction was authorized by you, or you have not kept your card or PIN secure, we will not refund the transaction amount.