Acknowledgement of assessment re-submission

I enrolled with Mancosa July 2019 intake ( Bcom Hons Supply chain Management). I've made a Re-submission for an assignment 14 April 2020 at 16:24 module name: Supply Chain Risk Management (SCRM). Mancosa declined the fact that I 've submitted hence I forwarded a proof from ***. which serves as a notification of receipt. I 've been calling since June 2020 cause I noticed that my marks were not loaded. I wrote exams and I waited. They later told me I must re-register again. I feel my right's were violated. Please assist