Personally, I'd be going to another financial institution, including taking all my accounts. Waste of time trying to argue with a monolith. Loss of business is probably something they can understand though.
Your situation reminds me of an incident years ago when I filled up with fuel at a petrol station just prior to heading over the Great Dividing Range. The vehicle began hopping before I'd even left the station, so stopped, went into the office and was basically told to go jump. As you can probably guess there was a large amount of water in the fuel...somehow I managed to get to the other side of the mountains, but was never able to do any thing against the oil company, as "it was considered TBTS" (too big to sue).
