In day-to-day shopping creditcards are very rarely used, but I'm pretty confident that for internet purchases creditcards aren't that rare. And as far as being banned goes: of course you first raise the issue with Amazon. Amazon says its an independent seller, go deal with them. You try to work it out with the seller, he doesn't budge, you show him the law. Still doesn't budge, you raise it with Amazon again. If Amazon doesn't budge, tell them that you are lawfully entitled and will do a chargeback, and that they can deal with the independent seller acting illegally (and if they're smart they just chargeback the seller). If they would still ban you then, that will be one hell of a juicy court case.