ServiceNow User Experience Design interview questions

The interview process goes fast, however the experience really sucks as there is no feedback for the rejection and there is no recruiter to organize the interview through the process. They asked me to book the flight and hotel for the onsite interview myself. It's really bad that they asked me to complete the design exercise to improve their current product even though they said that they won't plan on improve the current product. When I was in the onsite interview, the team spent lots of time talking and discussing about my design solution and they've shown great interests in those ideas and asked me elaborate on that. After one week, the team gave me the rejection without any specific feedback, which made me feel like they just asked me to do some free work for them to improve their product and kick me out after stealing my ideas. I would advice any applicant be mindful of sharing your own thoughts on their product.