Just an update in case this thread comes up in a search:

If you booked your tickets on bahn.de, the regular call center whose number I listed above will be able to provide information on your trains, but not on changing your ticket. The number for the internet call center is 01806 10 11 11, but the number of qualified English speakers they have is limited. However, if they inform you none are available, insist on having them try their English -- it's usually very good anyway. (Even though I speak German, I tried to find an English speaker as an experiment.)

Also, due to the flooding I thought my trains had been cancelled since they no longer showed up on bahn.de using the original search parameters. When I searched for each portion on legs, though, they were all still there, albeit with the previously mentioned delays.