American Advisors Group Software Developer(.NET) interview questions

I applied online and the recruiter reached back in a couple of hours to set up a phone interview. Phone interview was all questions about my background and technical skills, why I wanted to leave the current company. I got invited to on-site right after the phone interview. On-site was mostly questions about projects I had worked on, what I liked to do. At the end, I asked the team lead and hiring manager some questions about the team, projects, and tech stacks. I received an offer two weeks after the on-site interview. I did sign the written offer , passed the background check, and gave two week notice to my current company at the time. Two days before my start date, the V.P of Software Engineering called to tell me that they no longer needed a Software Developer and rescinded the offer.