Originally Posted by JJeffrey

Yea, AA can't force parters to open up award space so asking for any options on BA will make things exponentially harder, I wouldn't go that route.

I always use Google Flights for any search like this. Searching just "NAP-CLT" it doesn't show up, but searching NAP-DFW + DFW-CLT it does (assuming it's available on your specific date).

Do you remember what the mileage price difference was between F and J when you booked? I would call AAdvantage Customer Service (800-882-8880, not the usual EXP line), tell them you were downgraded on the PNR, and ask for the original mileage difference. They may not agree to all of it but it will at least get the conversation started. You could also message customer relations at aa.com or try via Twitter, but they would be my 2nd and 3rd option if AAdvantage CS doesn't get anywhere.