To cancel a credit card transaction, contact either the merchant on the other side of the transaction or the credit card company. Which you should contact first depends on whether or not you think the transaction is fraudulent.
When You Think the Transaction Is Fraudulent:
If you want to cancel a credit card transaction because you think it is fraudulent, the first thing you should do is search online for the name of the biller, as listed on your credit card account. Sometimes, legitimate transactions can lead to false alarms simply because a biller’s corporate name isn’t as recognizable as the brand name a consumer really does intend to pay. If that clears things up in your case, great – crisis averted.
However, if you still don’t recognize the details, you should definitely call your credit card’s issuer (the number is listed on the back of your card) to inform them about the unauthorized transaction. Even if the issuer can’t cancel the transaction before it goes through initially, you will not be on the hook for any fraudulent purchases made with your credit card account. All credit cards give users a $0 fraud liability guarantee.
When You Just Want to Cancel the Transaction:
If you know that a credit card transaction is legitimate, but you want to cancel it because you changed your mind or made the purchase by mistake (or any other reason), take your request directly to the merchant the transaction is with. The credit card company won’t be able to do much about a legitimately authorized credit card transaction. They might be able to instruct you on how to cancel future transactions if the card is being used for a subscription or other recurring purchase, but that’s about it.
Your chances of being able to cancel a credit card transaction made online figure to be especially good. Check the merchant's cancellation policy. Some provide a small window in which you can cancel a pending transaction. Just bear in mind that in this situation, an order may show as canceled before the transaction reversal posts to your credit card account.