When things still don’t go as planned, how do you respond? Do you fall back on the documentation and blame the customer? Do you blame the developer for incorrectly estimating how long the task will take? Both traditional and agile methodologies allow you to take these approaches. Rather, simply state the facts and involve the customer in these discussions. You’ll find that almost everyone understands some things are out of your control; The true test is how you deal with these events. You can hide behind your “contract” or you can have an agile mindset and put the issue out in the open to be worked on collaboratively.
Agile Manifesto value: Customer collaboration over contract negotiation
The customer at the end of the day cares that an engagement is clearly stated and handled in a professional way.