corporate-wage-slave

Welcome to Flyertalk and welcome to the BA Forum, I'm sorry this event brought you here, indeed you may well have got different advice had you raised it here first, I don't think your plan was efficient even if BA had done as you suggested. All you can do in this space is keep calling BA, in case an agent takes pity on your case, but I rather suspect they have put notes on your booking and therefore won't budge. If that's the case all you can do is raise a customer complaint after travel and then potentially take the matter to either a small claims court or CEDR, a dispute resolution service. There is some more information about this in the EC261 thread, which you will find via the BA Forum Dashboard.

EC261 does give you some protection in this space since this is the area where BA have to offer a rebooking, which it appears they have not done, from what you have said, and furthermore then treated you unfairly in the way they made changes to your reservation. I doubt you can do much until you do travel, but you can in theory pursue BA for whatever it is that you are out of pocket. At this stage I would make a note of the sequence of events and phone calls, since your memory may blur details over time. You can also seek a data protection disclosure on your booking and what personal information (ie phone calls) exist about the booking. They don't have a choice about that, it has to be disclosed to you. I guess you could have a dialogue with your credit card company if you believe you have paid for one thing and received a different thing altogether, but you best work on the Section 19 rights with the credit card company first, since this is sometimes more complex than it looks.