Sam's Club interview questions

I applied on the website after seeing the job posted on indeed. It took about 2 weeks to get an email for an interview. You get sent a form where you can schedule your own day and time for an interview. Well I set my appointment, and on the day of my interview I showed up at the location, and informed the person working the front door that I had an interview. They called the supervisor that I had the interview with and she came out and met me, and told me to fill out a shift preference sheet. I filled it out in less then 2 minutes, then waited almost 40 minutes for the supervisor to come back. When she came back she told me that the position I applied for was not even open and she doesn't know why I was given an interview. I showed her the job posting and the e-mail that I got, and she said pretty often this happens because it's an automated system. So I traveled 30 minutes and wasted my time and my money for nothing. I let the supervisor know that I was open to other provisions and she just said that she would call if there were other openings.