Aegis Protective Services Business Development interview questions

Applied to a Business Development position online and received a call that they were interested and would like to set up an interview. I called them back a short time later and left a message for the manager I received the call from. After my message was ignored I called again and left a message at the front desk and eventually emailed the manager. All of this was ignored. This came off as highly unprofessional and left myself wondering why request an interview and ignore the candidate? By the way, the position is still open to this day.