Valcon Consulting Project Manager interview questions

Extremely poor and unprofessional recruiting process for such a big consulting firm - further details below. The recruiter messaged me on LinkedIn in regards to my application, and followed it up with a phone call - pretty standard. He then said he'd send across more information about the company / benefits package etc, which I never received. 3 days later, the hiring manager rings me on my personal number completely unscheduled and proceeds to do an interview which lasted about 30 mins. The interview went really well and he immediately told me he was happy with my skills and would just need me to speak to the stakeholder for the account I'd be joining him on, so expect HR to reach out the next day. Not only did HR never get back to me, but all THREE of my follow up messages have been ignored. I also sent the hiring manager a LinkedIn invite per his request, which he never accepted. If you're going to ghost your candidates, maybe don't entertain a half hour conversation with them and make them think that you're happy with their skills / experience - or AT LEAST have the decency to communicate changes in recruitment to them.