In the case of card fraud, you don’t have a contract with the actual account owner. So taking that money results in THE COMPANY fraudulently charging a card. Again.

In the case of an actual dispute (non-shipment, etc) you do have an actual contract. However, this smells like extortion(?). You didn’t deliver on your end of the contract (deliver goods) but are penalizing the other side for your failure to deliver. It won’t go over well when you get the class-action suit, and all the little ones in-between.

Boy, it is not legal in ANY European Union country. Ok?

Especially online, the law says: Customer gets back ALL of his money, every cent.

You will be sued by customer protections in a minute if you act like that. Do you seriously run a business???