I would call AA back and see if someone else can fix it. Maybe remove the FF# altogether, then go to aa.com and try adding the CX number back? If that doesn't fix it and the next agent continues to profess an inability to resolve the situation I would escalate with AA. You have CX status, and it's AA's obligation to follow their own procedures to allow you to book the seats you want. I consider it to be lazy for AA to try to blame CX--as if the AA agent would even know what "CX are telling" the AA computer, it's not like she can see what interactions are happening on the backend anyway! Seriously...