Originally Posted by BA or bust

I think that is the issue. The agent made the mistake so AA rectified it. BA, or for that matter any other organisation, would say that your mistake is your problem. Having said that, I think you should contact customer relations and explain what you were trying to do and say that you were confused by the process. State clearly what you originally booked and what you were trying to change to, so exact dates and flight numbers. There is a very small chance that the cancellation process will not have completed and they might be able to resurrect it and treat it as a change, but don’t be upset it they cannot. Good luck.