This is an accepted solution.
Sorry to hear that you've had some issues surrounding your billing, and closing your store. Once a store is closed, any pending / final invoices will be charged, and after this, there will be no further billing. In order to look into this specific situation further, you will need to reach out to our Support team directly, since we are unable to provide account-specific support through the Shopify Community at this time.
Our Support team would be happy to continue assisting you through live chat, email, or callback. Please visit https://bit.ly/3cJkx8V and log in to your account to create a support request.
Since this is the next step I've marked this reply as the solution for the benefit of others who may discover this topic. Thanks!