None. You did not pay for the tickets as required by the contract and so the unticketed reservation auto-cancelled. An email advising you was a courtesy, but certainly not required.

I would first figure out what went wrong with the CC? Why was your charge declined? It is extremely odd that your CC issuer did not notify you.

Your approach should be to call AA back and carefully lay out your case, e.g., that AA should at a minimum as a customer service gesture, give you the ticket price as it existed on the day the reservation auto-cancelled. If the agent declines, ask to speak with a supervisor and a second tier supervisor after that.

Getting AA to open up lower-fared inventory on TATL during high season is going to take a lot of goodwill from some agent, so your approach will matter greatly.

Water under the bridge for OP, but for others, until you have an e-ticket # (not a PNR) for each segment, you have functionally nothing. That is especially true where there is a payment problem.