Poor service for students

I am a student at unisa. I have registered for second semester, made payment with the wrong reference of which i acknowledge my mistake. I have been calling unisa holding for more than 2 hours, i sent emails including proof of payment so that my initial payment can be rectified for me to study but no one is saying anything, no one is answering call centre phone. Even now as im writing this im still holding to speak to someone. The only way to get help with unisa is to go there physically but now due to Covid we need to rely on phones and emails but there is no one to help on these facilities. Can i get assistance as i need to study this semester. My student number is ***3.