Rude Invigilator

So my sister was writing an exam at 8 30am today at DLI hall. We arrived there at 8:28am and there was an african lady who said she was one of the invigilators and refused to let my sister go in and write the paper. She spent more time speaking to us and being EXTREMELY rude instead of letting her in to write the exam. I thought unisa were supposed to care about the education of students first and foremost? The invigilator refused to give us her name and told us we must get out and go the the enquiries department at unisa. My contact details are ***. This lady has to be delt with accordingly.