The Bahn Card from hell

I just thought to mention a salutary tale here. Last year my father bought a train ticket at a German rail station and the clerk persuaded him to get a Bahn Card as well. So far so good. A year later a new Bahn card arrived in the post with a letter thanking him for renewing the card together with a bill for the renewal. (40 Euros IIRC). As he didn't want one any more, he sent it back with a letter saying he was no longer interested. The following week, a replacement card arrived with a letter acknowledging the cancellation for 2013, and a final demand for the card for 2012. He sent this back as well. Two weeks later yet another replacement card arrived, along with a bill from a debt collection agency with a demand for 88 Euros.