For customers who settle transaction by credit cards, if you do not request and specify the exact amount of refueling, Shell usually preset pre-authorisation amount that is sufficient to cover that transaction to ensure the transaction can be settled smoothly*. If the preset preauthorization amount is more than the exact transaction (""residual amount ""), the bank will release the remaining credit to customers within 30 days regard to its policy.
*Pre-authorisation is the market practice of petrol industry. Since fuel is not returnable upon refueling, to protect the mutual interest between customer and the company, we need to ensure customer’s credit card has sufficient credits to settle the payment before refueling.