How do you Remove a Credit Card from Arc?

I've had two credit cards "saved" onto my account, and successfully removed one of them. But I still have credit card information for one of my cards "saved" to arc to buy gold. It's the option that allowed you to easy click "buy" gold without typing in information.

I want to remove this information, but selecting the card information and clicking the "romove" button on the right of the screen, when during the process of purchasing gold does not work. After clicking "remove", the info dissapears. When I relog onto arc to double check it's removal, the credic card information repears, as if I never clicked "Remove".

Please share with me how I can securely remove my credic card information.

Thanks!