I bought a Probe-Bahncard just a few weeks ago, and this is how the online process now works:

- You buy a "trial card" which is valid for three months
- Having bought the card you can immediately print out a temporary card which looks just like a train ticket and which is valid two months
- Your plastic card is sent by post

If you don't want to continue with the card after the three-months trial you have to write and cancel the contract (that's how things generally work in Germany.... whether it's your Bahncard, or a magazine subscription, or your membership of the pigeon fanciers' club, it's always an ongoing contract which you have to cancel a set number of days/weeks/months before the renewal date)