I am in Germany, and basically they do not accept your cancellation via writing to the customer support, but require you to call a callcenter, which is extremly hard to reach (either they do not pick up, or the connection quality is so bad that they don't understand what you're saying). In short, I did not succeed in that.
Rejecting the written cancellation and requiring to call is both borderline illegal, and an insult to the customer. Everyone involved knows that this is a just a maneuver to nudge you to give up on it, and that this requires me to waste vast amounts of my time trying to call a shady callcenter – that is just an insult to me, and it also destroys the NYT brand.