Incorrect pro forma invoice for incorrect payment plan issued

I have app**** for a BCOM Honours programme and selected the cash option. I have received a pro forma invoice for payment plan which is more than the cash option that I have chosen. I have paid the registration fee so long since I was scared of losing my place in the programme. Now I am struggling to get a correct pro forma invoice with the outstanding balance for the cash option. The person that assisted me is not in the office and registration is closing at the end of February. Proper assistance and the correct invoice with the outstanding amount will be greatly appreciated!