Something similar happened to me in Italy on my way from Bologna back to Rome in which TrenItalia's onboard staff managed to have me fork over another €102 and saying the €160 ticket and seat reservation I bought the night before weren't valid. I had my credit card company dispute the charge when I got back home and was given a "temporary" credit in case my card company lost the dispute. 3 years later, I never heard anything back. In retrospect, I looked it up and apparently due to my bad Italian comprehension, realized I didn't validate my tickets at the station, just hopped on board. Oop.

Good luck anyway! Here's hoping they will accept BTC.