Disappointed in this insituation

I am registered with UNISA for a programme in project management. Of the 14 modules I have obtained 7 distinctions, 6 passes & 1 fail, a fail of 20%. My DP for the Project Communications Management module was 80% and I have since been granted a mere 5% for the POE (Final Assignment) which has resulted in me failing. I have requested a remark which I have been declined, I have written to the department administrators who have not given me ANY FEEDBACK. I have even gone as far as calculating my marks using the UNISA semester mark calculator and the marks STILL DO NOT MAKE SENSE TO ME. I do recall receiving my 1st assignment mark for one of the modules, which is in a form of a MCQ that I had supposedly done terribly for it, however I didn't dispute the mark, I just told myself I should focus and work harder on the final, then the marks changed on the UNISA system, with no apology of explaination for that matter - I assume they realised they'd marked me wrong - if at all I was the only one. I am repulsed by this inistuation which I have entrusted with my education, they simply DO NOT CARE ABOUT THEIR STUDENTS. I've been told this is a UNISA THING, should we continue to entrust in them?