It's a cancelled number, but what happens (this happened to me on xbox live) is that they continue to charge it because they've got an active pre-authorisation. So when they're charging you, they're actually charging that pre-authorisation. If a different merchant were to try the card, it would fail.
Microsoft charged me for two years after the card's expiration date until I noticed.
Microsoft charged me for two years after the card's expiration date until I noticed.