It generally only takes a couple of days for transactions to fully process and post to your account but could sometimes take a bit longer depending on the merchant and the transaction type. Some e-commerce purchases won’t post on your account until after the merchant ships the item, so that could be the case.
In other cases, like at gas stations, hotels, or with car rental reservations, the merchant puts a hold on your account for the service before it takes place, and then releases the hold later, so it may take a bit longer for the transaction to post or be removed from your transaction history.
The fastest way to resolve this issue is to contact the merchant directly. If they’re able to remove the pending transaction, it should be reflected in your account in about 24 hours.
If they’re not able to help you, pending transactions will fall off automatically after 7 days.