What is the best way to contact the db bahn from the U.S. with a problem. I booked online tickets which I was able to print out with a bar code. I am supposed to show this with my credit card. The only problem is this particular credit card was stolen and American Express replaced it with another with the same digits except the last 4. I don't want a fine because of this and need to clear it up before I go in June.
Thanks!