Beam Logistics interview questions

HR arranged a phone interview via email and she called at the agreed time "via WhatsApp". I mean calling on WhatsApp is fine with friends or someone I know but for job interviews? It just makes me think how cheap this company would be, can't even afford international calls. The connection didn't work due to some technical issues which was quite unfortunate (I messaged her I could hear her but obviously she could not hear me) so we ended it and I thought she would email to reschedule but nothing. How unprofessional everything was already. Anyway I sent her an email probably a day after and we rescheduled. I changed the network and everything was fine. Mostly it was all technical questions but I was not sure if she was following up with my answers and rather, I had an impression that she didn't understand me at all. She never emailed back and I didn't bother emailing back either. Overall it was a weird experience and I felt the way handled was quite unprofessional and I didn't even want to proceed further