When and how should I lock my card?

Follow

If you lose your card, you should access your Viva Wallet account immediately and select the "Lock" option displayed on the main page. If in the meantime you find your card, access your account in the same way, and select "Unlock".
However, if you cannot find it or if you have reasons to believe it has been stolen, then apart from following the "Lock" option, you will need to call 13855 and report the incident. You can then ask for a new card through your account management interface, by selecting “Reissue”.