I once left some headphones in the seat pocket, called about them about it with the person being very helpful. About an hour later I got a call that they were found and I could pick them up when I wanted. This seems to be quite different to your experience. I wonder if being NZ*E at the time had anything to do with it?

The being too busy and hanging up isn't what you'd expect to happen. Even if it was by accident, they will have known your frequent flier number and will have been able to get your contact details. This isn't good customer service at all.