You can temporarily freeze your card if you are not certain that you have lost it by clicking on the card icon at the top right hand side of the summary page. Then, click on the ‘freeze’ icon. A pop up box will ask you ‘do you want to freeze your card?’, select yes.
Or, if it has been stolen, damaged or lost and you need to order a replacement, click on the card icon at the top right hand side of the summary page. Then, click on ‘account details’, scroll to the bottom and you will see the option to click ‘replace card’. Select the reason for the request and a new card will be ordered.