Something similar happened to me, but with Lufthansa. Canceled my flight 1 day in advance and told me to take a hike, didn't even bother to find/recommend another flight. Germany has really deteriorated, it's no longer matching its past reputation of getting things done.
With a flight, an airline that cancels a flight with less than two weeks notice owes you cash compensation of 250, 400, or 600 Euros depending on the length of the flight. The airline can only avoid this obligation if the cancellation was due to extraordinary circumstances outside their control.
A similar regulation for trains would likely tighten up reliability, though it could also raise ticket prices.
I think the time limit to request compensation under EU261/2004 in Germany is 3 years. If this happened within the past 3 years, you can demand that they pay you.
