Oh yeah, I've had one of those several years ago. It was a Bahn25 and I got a new one in 2 months and got sent a bill for it. Then, I called them because I couldn't cancel and I tried to tell them about this. At least at that time, the customer support knew about this sneaky practice, and would, on request, allow you to cancel it manually.

I did get a debt collectors post about my unpaid bill and I had to send around emails to them as well that I was pardoned and I didn't use the card at all. I don't remember if I got a confirmation about it and that's why I still have it on my records. After like 7 (8?) years, who knows when they would go under and then come up to me that I owe them like half a million in unpaid debt.