I tried calling AA again and the agent said she had to check with their resolutions desk. The answer was as expected that they couldn't do anything since the ticket was not issued by them. I don't know if calling their US number would make any difference as the AUS number seems to always go to their call centre in the Philippines, and the agents there either have no clue about *ONE* or not willing to help. I saw on the forum before that some people were able to get assistance from AA RTW desk but I don't know how you can contact them directly or if the team still exists.
I'm now waiting for MH to get back to me. I had to call their elite hotline as the normal helpdesk agents all said they had no access to the system to view *ONE* availability. Even with the elite hotline agent I had to be quite persistent to get anywhere. First I was told that since my booking was done online I need to manage it through their website and she couldn't change anything for me. After telling her that their website doesn't let me change flights, she then said because only the AA flight was cancelled I have to stick with AS from SEA - SAN, and there is no AA flight to SEA until 30th Nov. I told her I could see 15 other flights on 22nd on the Oneworld website for LON - SAN but she said she couldn't see any on her end. After a bit more back ane forth she finally could see those flights but since these are BA flights and not transiting through SEA she couldn't book any of those for me. I told here the BA flights are actually all code shared with AA so couldn't she just book it under AA. She said she has no authority to book code share flights and had to wait for her manager. She got back half a day later and asked for couple more days as they need to pass this to another department to liase with other airlines to see if they can get the seats and there is no guarantee.
I wish I could use up all 16 segments but I will be travelling with a toddler and newborn. I only booked *ONE* because I have to go to DFW and flights are ridiculously expensive from AUS to DFW at 2/3 the price of *ONE*
I have noticed that the base fare for *LONE4* has already gone up by AUD$300 this month since I booked it. Otherwise I would probably be better off just cancel the booking and rebook with another airline.