PredictSpring Staff Software Engineer interview questions

I regret that I didn't believe one of the interview review at Glassdoor, this company was wasting my time and I STRONGLY recommend you NOT to apply for it. The entire process took more than a month. After the two round of phone screens, they said since I don't locate in Bay Area, before inviting me to onsite interview, they will give me another project to complete. The project is about design and implement a entire API server. They said it should take me about 10-12 hours to complete, but I found it's about at least 20-30 hours work. Anyway I completed it with detailed documentation and fully working server. They reviewed it and said their CEO and VP of Engineering would like to talk to me as well. OK, then two more rounds of phone screens. Finally, they said they will fly me to Bay Area for final round of interview. I wait for more than a week then they said there are some changes in their end and this position is no longer available. I feel like they don't want to hire people at the beginning, why wasting both of our time??