Blocked student account despite having paid outstanding amounts

My name is Andiswa Mayekiso student number ********** 3

On 11 January 2018, I visited Unisa Parow campus to settle my outstanding balance of R1200. Upon my arrival I was informed that my account was handed to ITC and blocked which then meant I couldnt register. I was informed to pay the amount through ITC which i did. My mistake was that i typed in my reference incorrectly. when I went back to Unisa to explain they indicated that they could verify that I did pay and told me it could take weeks for the error to be rectified. I am stressed as I cannot register and I do not know whether this could be rectified by the due date for registrations which is 28 January 2018. Please help