Sunrun Front End Software Engineer interview questions

The process was smooth. Initially I got a call from the recruiter she setup a technical phone interview where I was asked questions about frontend development, best practices and JS. Then I was called for onsite to San Francisco. They had 5 interviews and the interviews went pretty well. I answered almost all questions correctly and perfectly. The interviews seems pretty happy and impressed by my answers and they told me they will reply in 3-4 business days. I got a reject on the next business day and it was a automated reply from the system. I emailed them to know the reason. No reply. They do not have the courtesy to even personally reach out to the onsite candidate.