O2 Sales Operations Manager interview questions

It was supposed to be a video interview with the hiring manager for which the person had their video turned off - strange! Their response to all my answers were very positive but looks like they had already found someone for this position, as I got an email response from the recruiter an hour later stating they wouldn't continue with the process. Really unprofessional of a company to waste people's time and go ahead with an interview if there was no intention of hiring.