As a matter of fact, your card issuer doesn’t have the authority to cancel a pending payment until it’s finalized. That’s why you will need to skip your card issuer, and directly contact the merchant who placed the charge as soon as possible, preferably within one or two days. The merchant will be able to order your card issuer to release the funds. In order to convince the merchant, you will need to gather all the transaction data you have, including details of the product or service, order number, charge information, and so on. You may also need to document all written and verbal conversations with the merchant.
If you notice a pending transaction that you don’t recognize, which can be a fraudulent purchase, it is important to contact your card issuer, to help you monitor the transaction and reduce your liability if, unfortunately, this charge still eventually posts.
Reversing a finalized transaction is actually easier than canceling a pending one in the United States. With the existence of the Fair Credit Reporting Act (FCRA), you have the right to dispute charges for billing errors, including unauthorized charges such as fraud, online or in writing. Banks are required to acknowledge a disputed transaction within 30 days following the reception of the complaint. Then they are obliged to resolve this dispute within 90 days following the complaint.