Fastned interview questions

Applied on their website and had a first call with the HR a few weeks to month later. Was then invited to their office for next round with hiring manager. Finally, was invited back for a case study as a final round. Ultimately, the HR told me that they were not looking to hire anyone and that they would post the job online again but with different responsibilities.

I had my initial interview with HR and then I was assigned a task which should supposedly take 10 hours but the according to the requirements it took much longer. After putting all my efforts I submitted the assignment and it was rejected due to very basic and biased reason. It was really demotivating after putting so much effort.