I'm not sure if it's exactly the same, but I had a similar issue a few years ago. Reserved a private compartment on a sleeper. Turns out that car wasn't attached and the conductor found me a couchette to have all to myself. But, it didn't have the small bathroom and some other differences.

He suggested I take it up with the station agents upon arrival in Munich. Unfortunately, the train was rather delayed and I had to head directly to the airport to catch my flight.

I ended up filing a dispute with American Express and they were able tor resolve it for me. You might give your credit card company a try - no cost to do so and takes just a moment.