Blocked from manage booking

I had a similar experience over a few attempts speaking with their call centre. I needed to change the name of a passenger and for that I had to pay for another, more expensive ticket, which I told them I wasn’t very happy about because I’d paid insurance to be able to make changes but was told I couldn’t. Both times I was asked to hold multiple times for no specific reasons firstly over a period of half an hour the second time over a period of 1 hour. Both calls ended with them saying they couldn’t hear me and then them hanging up abruptly.
In the end I tried to change my booking online and it seemed as though they’d blocked me because I couldn’t get past “verify” that I’m not a robot, it kept on freezing up. Now I can’t change the booking and will have to forfeit a ticket, very disappointed to say the least as I have booked 2 more trips in the new year with them.

Australia-Melbourne - Tullamarine