Since you booked through AA and the flight is an AA code share, AA is responsible for getting you there. That also means that if they put you on a different non-OW carrier, you still get the miles. Carriers (not all) cover each other for irregular ops, but I don't know how this one fits (btw,you may have to email them afterwards to request and explain, but you still get the miles). If you are not getting the answers you like, ask to escalate. Not all employees know all of the rules. The flight was cancelled, AA failed to notify, the flight is "AA", therefore they have to make it right. Decide what you want (check into flights by all carriers yourself) and if you need a hotel stay. Also decide on the hotel, but be reasonable. Be polite, explain the situation, tell them calmly that it is unacceptable and what you need to make the trip work. Be pleasant but firm. When all is said and done after the trip, email customer Service and tell them what happened and how it worked out. Give kudos where deserved (someone who tried to make things better) and penalty flags for failures. If you are not an AAdvantage member, sign up now and add it to your itinerary. That will give them a place to deposit miles as compensation for the hassle.