Question about UNISA - Math PhD by research

I am posting this question as a sequence to early posting on "Math PhD by Research" here. Let's assume for the time being that I have finally settled down with UNISA. I have this question on UNISA.

We who have been living here in US may have taken it for granted the open and casual communication between professors and students. For example, a department chair professor would feel comfortable responding to an email request even from a new freshman -- an example of egalitarianism in its best. But it may not be necessary true in other cultural settings.

Here is therefore my question to those who have gone through PhD program from UNISA: How do you characterize your relationship with your supervisor? Is he/she open and responsive to your requests? I think this question is relevant considering that a productive supervisor-student relationship is pivotal in a PhD program.

Especially, I would like to know more about Dr. ZE. Mpono in this link here, whose research interest is the one area I am interested also. I would appreciate your opinion if you happen to have had him as supervisor in the past.

Thank you very much for your time and effort.