You know why this is, right?
(Just for anyone else's benefit that doesn't know) - When you go to the card payment screen, the page isn't encrypted or secure! Usually when you're using a reputable online store there is a padlock to the left of the "https://" on the web address. Then when you put your card details into there, it actually goes through a third party. The online shop never see's your card details! What you're actually doing on these reseller websites is putting your card into a simple form that allows them to see your card details at a later time and charge it manually using a card machine or online payment portal of their own. This is why your card was cancelled, because to your bank, you've suddenly just travelled all the way to china and paid for something in person! It's a good thing they stopped it really.
Just to be crystal clear - They save your card details and then manually enter them into another payment system in order to charge the card and get the money from it. It's essentially the same process as if/when you give your card details over the phone to pay for something. So it's not inherently a bad thing, it just depends if you trust the reseller with your card details or not! I mean, they delete them all after they're done right?..... right??