How do I stop transactions from being processed on my Apple Card?

You may need to provide an example of a transaction you want to stop.

• A subscription is a legal contract with a merchant and to stop a charge, you would need to cancel the subscription. You will find that any VISA/Mastercard use Automatic Billing Updater (ABU) to carry to subscriptions to a new card number even if you request one.
• If you are the Organizer of a Family Sharing plan using Purchase Sharing with your Apple Card, then shutting off Purchase Sharing will prevent family members from making charges to your card.
• If you are talking about the Titanium Apple Card, then you can lock the card from purchases, although you are still responsible for your subscription obligations. This is useful when you have lost the card.
• If you think your card has been compromised, then you can request a new card number.
• If you made a purchase and your card has not been charged yet, you will need to contact the merchant to prevent the transaction. This is true for any card you may have and can dispute charges if it occurred due to fraudulent behavior.

Please provide more details related to the challenges you’re facing regarding your Apple Card Mastercard.