In this situation you would tell your immediate superiors about the situation and you wait for their orders while completing the work on your hand. On specific orders about managing the branch you will be explaining about the situation or work currently you are handling.
Always remember while answering this question you need to be careful about addressing points, don't move into the negative side because it can give out negative vibes. Explain to him about the advantages and disadvantages about the product.
When answering these types of questions you need to specify a real life example about the situation you faced if you hadn't faced such type of situation explain to him how you can deal with an angry customer. It would be an added situation to explain about the possible scenarios.
If you have used logic and judgment in solving a particular problem then explain it to him otherwise politely say that you never faced it and explain him about the possible ways you would have approached at the logic (brain storming, decision making, etc).
If the work is huge the best way to get it done is to share it among the team leaders and members. First you would explain to the manager about the project size and then share it among your batch members for better efficiency. Answer this question in your own way and style of doing work.