You own your card financials. Ring your bank, and block the transaction. OTOH if there are identities bound up inside Amazon, ownership (well, rental) of digital goods, you could be cutting off your nose to spite your face here, but the banks have to respect your requirements with charges on your card. Its your card you own the right to decline a transaction you didn't authorise.
No, it is not common for helpdesk and case management to close a call. You probably will struggle to get Amazon to take that seriously but in the real world, this is not acceptable and a good player has a path to complain about this, which means call logs get looked into. I don't think it will happen here.