Spartan Software interview questions

Initial phone screen, followed by an exercise to implement GlobalSight software on Amazon Web Services,which isn't that straight forward, and can take you many days and cause a lot of frustration if you dodn't get it right the first time. Second assignment was to prepare a functional requirements document for a hypothetical localization project, which needed to include system diagrams etc. which again could take many days. They give you a week to complete this. I completed both these assignments excellent, putting in a lot to effort to be exceptional. They called me for an onsite interview and interviewed for almost 4.5 hours including the presentation I had to make explaining the assignments. They seemed very happy during my onsite interview as well and appreciated the effort I put in for all these. I paid 50 dollars for parking in SF downtown and incurred other expenses to make it to the interview. My only daughter's first birthday was around this time, and I let it go thinking I will do the assignments perfect, which was a terrible mistake from my part in retrospect. Anyway after all these and a few days after my onsite interview I get a email mentioning that I was one of the top candidates but they closed the position. I am assuming it has something to do with my H1B transfer( which I had requested in the initial screening itself) and nothing to do with my performance or skillset. I have nothing against the employer, but if there weren't serious about the position to be filled, they shouldn't have made a candidate go through all these, especially time consuming assignments. I regret the amount of time and effort I invested on this position and company, which was precious at that point of my career and life.