I would share BA's communication with the proprietor of your travel agency, and ask what, if anything, the agency intends to do to make you whole. If the agency did something wrong with your BAEC account, then the agency should set things right. If nothing wrong was done with your BAEC account, then you might have to go after BA -- perhaps through litigation, arbitration, and/or a complaint to the U.S. DOT. Your attorney should be able to advise you. Yet another possibility would be to bring this to the attention of a local TV or newspaper reporter who does consumer-advocacy stories -- especially if there were multiple customers whose BAEC accounts were affected. But first give the agency an opportunity to make things right.

Edited to add: Here are a couple of San Diego TV consumer-advocacy reporters:

https://www.10news.com/adam-racusin

https://www.nbcsandiego.com/author/bob-hansen-2/