The (US) banks I've experienced will give you an "incident number"[1], you can call the number on e.g. your credit card or bank's website and say you have an incident number and you'll be connected to a rep who can pull up the details.
[1]: or something like that, I forget the exact words
My card has an international number which is US +1-(AreaCode)-XXX-XXXX. It used to bypass the IVR and send you directly to the top of the queue to a CSR. Because who has time to putz around the IVR when you're paying .25-.50/min to make an international call. Sadly, because some customers figured it out, it just routes you into the queue.
[1]: or something like that, I forget the exact words