Nielsen Software Engineer interview questions

I got an interview chance with Nielsen Chicago office. I think it's just a pre-interview with HR and the duration should be about 30min. First time: asked half day off, sat there 30min waiting for the incoming call but nothing happened. During in the following emails, HR said she called me three times but it's a busy signal. Then we rescheduled it to 4/10/2017, and this time I’m gonna call her. Second time: asked half day off, called her on time, no one answers the phone, left a voice mail, sent out email asked if she can call me back, and called again 15 minutes later, again no one answers. I haven’t received any feedback or information yet. Don’t know what happened. Can’t believe this.

I talked to hr when they came to my college career fair. After two week i got selected for campus interview. They never got back to me with result.