If the client complains.
The client contacts you and complains that the delivery did not arrive on time. They are unhappy and want you to compensate them for their trouble. Of course, you can contact the driver who made the delivery in question and ask them. Most likely, they will say the delivery was on time. It appears to have been the customer who failed to record or receive the delivery on time.
This leaves you with a dilemma.
Discover the simple steps you need to back up your position.