The whole application process was a sad story. I believed until the last moment that this company was serious, but it seems that I was misled the whole time.
Here is my story:
I applied sometime at the end of January. I had my first interview in March. I had a good feeling about the company, the rotational programme and the employees after the interview. About 3 weeks later, I was invited to Superday. I attended Superday in April. It lasted roughly 3-4 hours. I had 3 individual interviews with management and a case study. As for the case study, I had an hour to prepare and then another 20 minutes for the presentation and 10 minutes for questions from the panellists.
After some time, I received a verbal offer saying that they were "impressed with my performance". I was even told (now I quote): "Don't undersign any other contracts".
However, my offer needed a CEO approval.
At first, I didn't think it was strange, as I was told that they will have another Superday and they want to hire more candidates. I received weekly or biweekly phone calls saying that nothing had happened with the offer yet. Finally, in June, I received a phone call with "good news" that the CEO had started approving offers for the Treasury department. A week later I was expecting a phone call with even better news. i.e. that they already have a formal offer letter for me. Instead, I received a phone call with "bad news" that they decided to cancel the entire programme. They asked me if I would like some other role in their company instead of the cancelled one. However, they did not have any suitable positions open at that point. I never heard back again.
I was looking forward to joining the ion team in September. It was very disappointing to find out that I was misled for 3 months.
This is not the right way to recruit graduate students. I invested a lot of energy into the entire process, not only during all interviews but also while waiting for a formal offer. Now I'm back where I was half a year ago, looking for jobs again.
I would advise to all other applicants to keep looking for jobs even if you have received a verbal offer. I learnt from my mistake and I hope that I will not experience anything like that again.