Jet interview questions

What a SCAM !! They had a video interview done by a company called Karat. I was able to reach an optimal solution to the challenge given , ran my code and displayed the output required. The interviewer agreed that my solution was "as optimal as it gets" and agreed with my analysis of complexities. When 10 mins remaining for the interview he gave me a tougher challenges and asked to discuss a probable solution. I was still able to discuss an optimal solution in given time and ofcourse he agreed to that in the interview that was been recorded. Then, I received rejection two days later. Fail to understand what went wrong, haven't experienced as framed and misleading as this.