When the delivery person arrives at the delivery address, they attempt to contact the customer. The app also notifies the customer of these attempted communications. The delivery person also waits for a reasonable amount of time at the delivery address.
If the delivery person is unable to deliver the order, the app provides a notification of the attempted delivery that wasn't completed successfully. All these contact attempts will appear in the app.
If a delivery person isn't able to deliver your order in these circumstances, you are charged for the order.