If I am in a store and the clerk says "we've upgraded you to the super deluxe gold thread shirt" and that's what I ordered, I would say so. If I received a note saying the same thing in the mail, I'd mumble an expletive and throw it away.
If the FD agent tells me I've been upgraded and I had paid for a suite, I would say so. If I checked in and had a note in my room from the manager that stated the same, I'd mumble an expletive and throw it away.