I've been trying to call 8 numbers since the 29th ...

I've been trying to call 8 numbers since the 29th of May 2017, I have had no answer, lines either ring, cut or randomly say that the subscriber isn't available. I'm worried as I had a doctors note and next to my results it says 'Absent from Examination', unisa have not acknowledged receipt of my supporting evidence and I'm worried that instead of writing a supp, I will have to redo the entire semester and pay off that again due to no acknowledgement of my paperwork.