Assignment Missing with no accountability!!

In the years of my education, I have never met a negligent and unprofessional institution like the so called University of South Africa #Unisa. I submitted my assignment in June and it went missing and they asked me to resubmit when I queried their marking process. I then resubmitted later in the year #2018highlights ,only to find that I will be awarded a zero for late submission even though I gave the lecture the case number after months of waiting for them to respond to my emails. When I followed up with the lecture,she was very ******** and asked irrelevant questions to the matter at hand. I asked for my for my marked script and then she never responded because I wanted to see how was I assessed. I have lost an opportunity to be employed as a teacher because of the gross negligence from this institution. They are not taking my calls nor responding to my emails. I am highly disgusted and disappointed by this behaviour of a not so great institution. I regret having to put my career in their hands. I am not sure what to do going forward!!! #Unisa. I hope someone with common sense from Unisa does respond to this. They have taken my money but no service at all. I have used all their platforms to try and communicate with them but nobody bothers to responds. Even their departmental secretary does not answer calls. I need service and my qualification for my hard earned money!!!