Veeva Systems Commercial Analyst interview questions

First, a simple HR interview, just a resume check. HR told me that this department is expanding rapidly. Then, I moved on to a manager interview. We had a very pleasant talk and he decided to move me to the next step, which is a case. They will send you the case one week before your interview, and in the middle of the preparation time, the manager will set a 10 minutes meeting for you to ask any questions about the case. This case will need at least 30-40 hours to prepare, and at that week, I had 2 mid-term exam. I decided to put all my effort on this interview because it was very important for me. Then, on the question meeting day, the manager told me that they would not move me forward because they did not need. I was shocked, and I asked again whether they meant I did not need to do the case presentation, and the manager said yes. I cannot understand why they don't tell me in advance so I don't need to spend my 15 hours on preparing the case. The communication is so bad. Also, I checked on their website after two days of the decline call and they were still accepting people to apply on this position. I strongly doubt their true reason of declining me.