VertiSource HR interview questions

I interviewed for the position and the interviewer said he wanted to schedule a second interview for Monday with the CEO, so watch for the email. All weekend—nothing. Monday morning I emailed saying it was great meeting them last week, I was looking forward to meeting with them again today but hadn’t seen the invite yet. No answer on Monday. On Tuesday I emailed again. On Wednesday I got a response they wanted to do the second interview Thursday morning, but I currently have a job and was conducting training all morning so I said unfortunately I wasn’t available until the afternoon. They scheduled the interview for the afternoon and when I joined the video conference, I was immediately told that they made an offer to someone else that morning and they accepted, so the interview was cancelled. I thought that was pretty unprofessional to string me along like that