Questions d'entretien chez CoLab Software

I did the first round with the HR, which was smooth. Then I did a second round with the hiring Manager and the director. The director was not paying any attention and never looked into the camera. after I passed this round I was asked to prepare a presentation. It was in the company template. I spent a lot of time on it and after a few days I just received an email from HR that it was not good. I had invested a lot of time, and there was no feedback at all! They did not even give me a chance to present it and answer questions. Afterwards, I showed it to other people, and they all told me it was very good. I see that after 3 months the position is still open and I believe this is a scam, they just make you solve their problem, use your ideas and do their work and probably use your presentation internally for themselves.