Vertica UI/User Experience Designer interview questions

It was one of the craziest experience. I was contacted by recruiter from Micro Focus. Initial phone screen and then 1 hour long phone interview with hiring manager. I was given couple of links to review and was asked for a feedback. After that I was invited for an onsite interview. It was 6 hours long interview with 45 minutes sessions with different team members. I presented my ideas about the product based upon the link hiring manager shared with me. I did share some designs and share some ideas about tools I use and different aspects of UX. Two weeks after onsite I was asked to share my ideas about their product via email and I was asked to share the design idea too and after 5-6 follow up email they said they are moving forward with someone else. I felt I was used for my ideas and they faked interviews just for brainstorming the UX part for the betterment of their product. Guys please be aware do not share your ideas and information in depth, tackle interviews with this company smartly.