One of the cornerstones of a strong (agile) team is their commitment to quality. Most of the time I see a superficial attention to it. Especially when it comes to - what most call it - non-functional requirements; these aspects that make the operations lightweight: availability, support, security, maintainability, adaptability.

I like how you formulate "Start at the end". If a team really has a strong commitment to quality, then one would expect a monitoring system to be in place, so that the company can proactively deal with the payment schedule.