Amazon reopened my seller account without telling me and sold an item that no longer exists. What do?

Amazon closed my account like 4 or 5 years ago after I deactivated all the listing’s and quit selling. After they shut it down, I have not been able to log into the seller marketplace site. If I tried, it’d tell me I need to create and entirely new account with a different email.

Well today I just got an email that an item that I had listed previously has sold and I need to ship it. It also let’s me back into the site but won’t do anything until I update my credit card number as that has expired.

How did this happen? Can I cancel this order without updating the credit card? How can re-close my account?

Or should I just say fuck it and ignore everything?