Zendesk Manager, Sales Development interview questions

Once I applied it took severally weeks for them to respond which is not normally uncommon however once they did make contact I had to answer several questions, some of which where double ups and others not articulated properly. Then I had the first interview with HR, everything seemed very positive and they advised they would pass me onto the hiring manager. After a week of not hearing anything from them I followed up with the HR who said they would find out what was happening to then be sent a automated email saying I was unsuccessful with no reason why. I personally spent hours of my time learning about Zendesk and preparing for 2 interviews to only be knocked back by an automated email. I feel like a company like Zendesk can treat people better than this.