GSK HR Manager interview questions

GSK Recruiter called 1 day after application submission. Had a positive conversation followed by a few questions. Recruiter stated he wanted me to skype interview with the hiring manager and would get back to me on date & time. He followed up with 1 option for a Skype interview which unfortunately conflicted with my current work schedule. I asked if any other dates would be available and never heard back. I sent a follow-up email and again never received a response. I find it very unprofessional when Recruiters do not close the loop.