TrueCar Software Engineer interview questions

I had four interviews: Recruiter, Hiring Manager, Coding, and System Design. I had one of the best coding interviews I ever had with TrueCar. I was asked to create three functions, which I was able to do with time to spare. I then had enough time to refactor the code so that one function could perform the work of the other three and be called by them. Afterwards, I received a rejection stating they didn't believe my knowledge of Ruby and React was sufficient. Mind you, I was never asked any React-specific questions. When I asked them to please tell me what I could have done differently, they refused to do so