Regardless it was worth rebooking and using the call back feature for customer service, as now I just checked flight fares again and they went from $817 on Wednesday to over $1,800 today. It seems BA was marketing their LHR flights from their old US routes starting in July, but then removed them. AA had lowered their prices to match. So it is possible that the system was experiencing some errors that day, due to some info a friend gave me that the PHX -London route at one point showed up as $1! Too bad the flight didn’t really exist!