Legacy Communications interview questions

Legacy communications was in contact with me for a total of one month. During this time, I was officially interviewed three times and had multiple phone calls with the company. It was implied at various stages throughout this process that the job would be mine and that I was the only person being interviewed. This happened for two separate positions, so maybe I am more naive for believing them. Firstly, I was interviewed to be an account executive and even did a task that took over one hour. when this didn’t work out, I was considered for a similar position and it was heavily implied that the position was mine and that no one else was being considered. After much back-and-forth that seemed positive, I was told that the position was filled by someone with more suitable experience. I think this is a very strange way to treat someone after investing a month of various interview tactics in them.