Practise one William Blair question

You recently completed a very challenging project. You then received an email from an internal stakeholder, with whom you'll be working frequently in the future, expressing concerns about the way you managed the project and dissatisfaction with the final result. You strongly believe that you managed the project well given the challenging circumstances, and that the complaints are unreasonable and rude. How would you reply to this stakeholder? How would you interact with this person in the future?