I have been trying for weeks now to get hold of so...

I have been trying for weeks now to get hold of someone at UNISA. I have even gone as far as trying every number I could find. Some of the numbers don't work, other phone just keep on ringing with no answer and the other lines stay busy. The one number I contacted was ringing and then cut out due to the duration it took with no answer. When it cut out I called back immediately and then that line was busy. How is this possible.......