Final answer:
If a customer pays early despite your assumption, inform them and update your records accordingly. Consider offering incentives for future early payments.
Step-by-step explanation:
If you assumed a customer wouldn't pay early but they have, you should inform the customer and thank them for their early payment. Since they paid early, you can update your records accordingly and consider offering incentives or rewards to encourage future early payments. It is always a good idea to maintain open communication with your customers to ensure smooth transactions and positive relationships.