YouVisit interview questions

I was contacted to come onsite. We agree to a time a week in advance. The night before my interview, literally at about 7:30 pm, I get an email saying that YouVisit has to cancel this interview. It said that they have selected another candidate for this position. First of all, if that was true, why would you select another candidate without even hearing out the candidate you already have scheduled the next day? Second of all, this company continues to post about this position on all the job sites daily. So I have absolutely no idea why they felt the need to single me out and screw over my day like this by rejecting me without even meeting me, after they scheduled an interview. I had to move around meetings at my current position for this, as well as take half of a personal day off from work. It was the most unprofessional experience I've ever had with a company in the interview process.