Answer:
Unsolicited supplies are goods or services which a business supplies to a customer without them having asked for such goods or services. The Australian Consumer Law prohibits a business asking for payment for goods or services that a customer has not requested. As a business, any invoices you issue must include the amount you reasonably believe you are entitled to be paid.
For example, a local mechanic is hired to do a minor service for a customer. While doing the minor service they notice a problem with the vehicle’s suspension. They fix the problem without asking the customer first and subsequently bill the customer for an extra $300 on top of the cost of the minor service the customer had agreed to originally. These actions would be in breach of the Australian Consumer Law.