Docusign Mobility & Benefits Administrator interview questions

I was contacted for a preliminary phone screening, but the interviewer never called on the day of. I wrote an email and left a voicemail to ask if she wanted to reschedule. There was no response on the next day, so I wrote an email again asking her to confirm if the screening is still taking place. She finally replied 2 days after the initially scheduled date and confirm another date for the screening. No explanation for missing the first screening was ever given in either the email or the subsequent phone screening. I understand that HR gets really busy, but this does not strike me as the most professional behavior.