Fund Recs interview questions

First interview went well with co-founder. They asked me to complete a challenge around their specific architecture and business, whichnI felt was beneficial to validate their own architecture (not really a company I would work for after I realized why they wanted such a detailed report). Free consultations I guess!! Project was about... Ingesting xls and pdf files (possibly containing bank transactions) Detecting anomalies with the data . Like missing or unusual funds transactions. Integration of a rules based workflow ( transformation and dq). I produced a comprehensive report but apparently I wasn't technical enough for them! The mind boggles... The CTO and chef architect was present but they didn't make me feel comfortable in the interview. It it ethical for a company to eligeltily seek few consultants to validate their own architecture.