I'm Miles from the Social Care team at Shopify. Sorry to hear you've been having issues with your billing.
There are a couple of things you can check to see what might be causing the issue. First of all, Shopify can only accept payment for invoices via a credit card or PayPal (PayPal is only available for non-US merchants at this stage). If you're trying with a debit card, that could be the issue. Try making payment with a credit card to see if that resolves the billing. You can learn more about our billing payment methods here: https://bit.ly/39LvNym.
If you are using a credit card already, contact your credit card issuer to see if they're blocking the transaction. Sometimes, banks may block transactions they deem to be suspicious.
If none of the above resolves the issue, you may need to contact Shopify Support for further assistance. To contact our support team, first head to https://help.shopify.com/en/questions and log into your store. Once you've logged in, you'll be prompted to ask about a topic.
Doing this will present you with links to relevant documentation on our Help Center, but there will also be an option to contact us directly if you require further help.
Clicking on this button at the bottom will then present you with the different support options available.
If you don't yet have a Shopify store or are unable to login, you can choose the "Continue without logging in" option at the start and continue through the same process.