Part 2 (two parts): The first part was simple; debug the solution (their working solution of Part 1) to identify why two the customers did not show up in the csv file. The second part was even simpler; write a letter to the client describing the problems.
Sigiloso
I managed to complete this part in less than 1 hour, but the interviewer wasn't present by the time I completed it, so I just sat their for a good 15-20 minutes trying to solve the issues (finding the issues was mandatory, but solving was optional). The error to one missing customer data was a duplicate customer ID. The second customer was missing due to an indexing error. I checked the loop(s), but I couldn't find the root cause. I wrote the email explaining the issues in the text document provided.