Infostellar Senior Agile .NET Developer interview questions

Their recruiter reached out to me, had a technical phone interview with the hiring manager followed by a video conference interview a couple of days later. Received an offer a few fays later and went through the on boarding process ONLY FOR THEM TO TELL ME THE POSITION IS NO LONGER AVAILABLE. I declined another strong offer to accept their position of a Sr. Agile .Net Developer and went through the clearance process, they suddenly stopped communications and when I asked, they said "the client changed the requirements and the position is no longer available." Who does that?? And not even care to let you know?? Horrible!! Be very careful!