The JNB call centre do not have full access and absolutely have all sorts of issues seeing seats that are available for sale. This call centre is an absolute disgrace and QF is a disgrace for continuing to use a call centre that still has not been trained properly and given proper system access...
Be a WP or above to not be treated with complete contempt.
Otherwise, file a complaint.
https://www.qantas.com/au/en/support/contact-us/customer-care-feedback-form.html#
There's a chance you'll get a call from a competent agent to sort things out.
Actually I have not.
But I did think of four more that I would be extremely surprised if any AFFer has ever been to.
1. KJOT - Joliet Regional Airport
2. KARR - Aurora Municipal Airport
3. KLOT - Lewis University Airport
4. C09 - Morris Municipal Airport James R. Washburn Field
And YJAC is...