i have no ideal what to do?

Go to the interview and use it as practice. Interviewing is a skill. And like all skills, the more you practice, the better you get. You'll find that your confidence level in an interview goes WAY up if you already know you do not want the job.

Don't be arrogant or a jerk. Go in with the attitude that you are genuinely trying to impress them. Then when they offer you the job, politely decline it.

Use the interview to raise the questions you now have about them, in an adult manner.

You don't give enough info on the company or the situation otherwise. Some places schedule the first come, first served after posting on job boards, so a quick interview is possible. Some companies have multiple interviewers and are 'training' them, which isn't cool but it happens.

Go prepared with questions. What you hear allows you to make a yes or no decision at the end of the interview, you can gracefully decline and let them know that you're not comfortable with the job being offered. It also gives you experience with the interview process and how to handle stuff like this.

Sure, either call and tell them you changed your mind, or just don't go

Just don't show up.

Just don't show up.
There is no national database for interviews. If you don't show up no one else will know.