Unprofessional and ********* institution...MANCOSA

I app**** to Mancosa for my honors degree yesterday and was told by the student advisor that my application was successful and I need to make the registration payment which I did and sent through the proof of payment. After a few minutes I got an email stating I need to pay an amount of R13200. Before I register. Upon querying this amount i was advised that it outstanding fees for my 3rd year which was during.the covid pandemic and I never received an income during that time and being a single mum financial obligations at home was a priority. When we were paid our TERS money I was offered a 50% discount from mancosa to settle my fees so that I could graduate which I did pay off. Now 5 years later I am being asked to pay this amount as I never had any communication from Mancosa Regarding the outstanding balance. The student advisor advised me that I must pay that prior to registration. Firstly I hope my registration fee is refunded and not absorbed into the so called outstanding fees which according to my knowledge was settled as per the settlement amount given to me. I can utilize that amount to register at another institution. Is it also legal to request payment after 5 years ..is this legally correct ???