Hey @Desidrop .
Thanks for reaching out.
That is a great question! If you are unable to pay the outstanding balance for your Shopify bill, Shopify will attempt to charge the card on file for the outstanding charge. If Shopify is unable to charge the payment method added to the store, the store will become frozen and will be deactivated automatically. With that being said, if you attempt to re-open the Shopify store, you will be prompted to pay the outstanding charge in order to have the store available to your customers.
Let me know if you have any questions.