Awaiting final invoice and refund!

Tempest - Reservation: TMIDR ********** RS2. We dropped off the car on the 2nd Jan and we are still awaiting final invoice from the Midrand branch. I called the call centre on Friday the 4th and they advised me it takes 3 working days. That has passed and the invoice is still not in my inbox. I have used the Centurion branch and always received my final invoice within 2 working days. Can someone please attend to this or let me know what is causing the delay