Amex Travel hold times have been quite poor lately. Last week I waited over an hour to chase a QF Ultimate travel credit reinstatement before the line dropped. I called the Plat Concierge line, explained what had happened and asked whether if they could push me to the front of the queue, which they were happy to do.
When I eventually got through to Amex Travel they acknowledged a significant backlog of QF credits waiting to be reloaded back to cards which is a manual process. For context I had two identical bookings made with TCs from two QF Ultimate cards - the cash refund hit both cards six weeks after Qantas cancelled the flight. It then took Amex two weeks to reinstate one of the TCs, the other is still outstanding after almost three weeks.
Something else to note is their terrible calling centre opening hours - 7am-6pm Monday to Friday. The Live Chat function has also been disabled for months (if not years) now.