"yeah, we're only giving you a third back because you took a first class"
"First class was cheaper than second class (which you reimburse fully), and I provided you a screenshot."
"Yeah, but on your screenshot there was a much cheaper ticket. That's the one we're paying back because you could have taken this one instead."
"That's not how you were doing it for the past three years, and besides, that ticket was a completely different schedule, non-modificable, non-reimbursable ticket, and the train had a MUCH different route, with a connection in Paris instead of the direct one I took."