When closing your store, any pending charges will need to be paid for. If you're unable to pay for the invoice and need to close the store, then you'll need to contact Shopify Support as they'll be able to escalate the request to our Accounts team who can assist with closing the store without needing to charge the pending amounts.
You can do this by logging into your store through the help center, searching your question/issue, then selecting "continue" at the bottom of the page that displays the search results.
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