Earnest Client Happiness Representative interview questions

After I applied, I had a 30 min phone screen with one of the recruiters. In typical phone screen fashion, we went over my work history and why I wanted to work at Earnest. Afterwards I was given a take home assignment with some sample email responses that were overall not too hard. Several days later, I was asked to come in for an in person interview with 2 team members, then 3 separate 1:1s with the team leads and the head of support. Each interview went over my resume and skills, why I wanted to work at earnest/why I was looking for a new position etc. The 1:1s felt like more easy going conversations as we went on separate walks around the block. Overall, I felt like it was a good experience and I always knew where I stood in the process. I was given an offer several days later, which I accepted. The weird part came when I received a call the night before I was supposed to start from the director of HR, stating that they were rescinding my offer. When I asked on what grounds were they rescinding the application, they dodged my question by saying it was private information, and couldn't tell me. This left a rather bad taste in my mouth considering I had already put in my two weeks and was left jobless without any indication as to why.