I have received a message to verify an online purchase I have not made.

When you shop online you may be asked to verify the payment by entering a one time passcode. This passcode will be sent by SMS to the mobile number we hold for your account. 

If it is not you attempting to make the online purchase, you should immediately:

1. Suspend your card so that it cannot be used in any further transaction attempts and then;
2. Check with family members to ensure they are not using your card to make purchases not authorised by you. If you know the card to be compromised then report your card as lost or stolen, and permanently cancel your card and then;
3. Check your account for any other transactions that maybe fraudulent and raise a dispute for any unauthorized transactions, and then;
4. Request a new card, so you can keep shopping using your Mastercard