What you are likely seeing is a credit card pre-authorization - a common payment tool used by Uber, Airbnb and many other service providers. This is a 'hold' placed on your account prior to the transaction, in the event that the transaction is successful. This is not a charge, but rather a 'hold' to ensure that your account can cover the cost of the order and avoid any overage charges.
If your order was unsuccessful, this amount will normally be credited back within 5 - 10 business days. If it has been over 10 business days, please let us know the order that this is in reference to, and we'll be happy to look into it!