Walmart Overnight Stocker interview questions

Took 2 minutes, asked basic questions I was wearing a graphic t shirt and sweatpants, right after a workout. I got the job and the interviewer was a very nice lady.

The interview went very well. I already knew what they are going to ask and I gave them the exact answers they were expecting. The interviewer told me that, I answered every questions correctly, but the position I interviewed for is already filled. I don't understand why she interviewed me for a position that doesn't exit anymore.