I actually made money accidentally with a BahnCard subscription. I canceled my BahnCard 50 within the first 14 days (which they have to conform to due to laws) via email (btw: before the starting date so I did not use it). They confirmed and send me back 100Euros too much money. Why 100Euro? I had originally used a coupon code that saved me 100Euro. Good guy as I am I told them via mail that they sent me too much money back. What did they say? No, can't be, Bahncard50 costs are the higher amount, the banking statement that I sent them must be of something else.

I was like... alright, no sense in arguing with them anymore.