Slack interview questions

I was delighted to receive a note from Slack to book an interview and responded with my availability however I did not hear back from the recruiter. A week later I received a carbon copy of the first email sent to me, asking me to share availability for an interview. I responded and a time was locked in for the next day. The recruiter did not contact me at the booked time and despite two follow up emails, I've heard nothing further. Completely understand that the scope of roles change or a candidate who was once deemed suitable is no longer the right fit but would rather the recruiter is transparent and communicates with me rather than abandon the process. I enjoy using Slack as a product but have to say that this very clever company appears to be not so bright when it comes to candidate experience.