Pharaohnz

I noticed that one of my flights with AA/AS from Heathrow to San Diego (via Seattle) in November, the AA leg was cancelled recently without me getting any notifications. I contacted MH yesterday as the first leg of my itinerary is with them, and the MH agent told me to contact Oneworld directly as they couldn’t make any changes to non MH flight. As Oneworld doesn’t seem to have any direct contact number I tried calling AA to see if they could help. The AA agent insisted that she could see the flight and it’s not canceled but she couldn’t tell why I’m no longer booked on that flight. She said there is nothing she could do as the ticket is not issued by them.

I tried MH again today and it’s been a nightmare dealing with them. I called 5 times and each time I got cut off after waiting ages for the agent to come back to me. Most of them seemed to have no clue about the RTW product. The last person I spoke to said that I might need to pay extra charges and then disappeared for 30 minutes to investigate. She then came back and said that the earliest flight she could find without any extra charges is the same AA flight 8 days later. She also said who ever issued me the ticket made a mistake as the ticket shouldn’t have been issued by MH, which I know is completely bonkers as it’s clearly stated by Oneworld the airline that flies the first leg is the issuing airline,

My understanding of the fare rule is that any changes to flights shouldn’t incur extra charges as long as it doesn’t require route change. Or is changing the transit point considered as routing change?

I can see 16 flight options on that day with either BA or AA via different transit point on the Oneworld planning tool but only one BA flight (AA code share) that transits via Seattle. So if I choose the AA code share flight I shouldn’t have to pay any fees
or fare difference?

Also isn’t AA responsible for finding me an alternative flight since they cancelled my original flight?