Rae from Shopify here.
Thanks for reaching out about paying your invoice. I'm happy to help look into this further, and provide some next steps!
When you log in to your Shopify admin, are you being prompted to pay for your invoice right away using an accepted payment method? If not, just follow these steps and visit the 'Settings > Billing' section of your admin and click 'Pay bill'. Let me know if you see any errors when following these steps, and if so, please also confirm which payment method you're using.
In the meantime though, I know you mentioned you were hoping to speak with our Support team about this directly, so if the above steps don't resolve this, you can contact our team for more assistance via our Help Center. Once you visit that link and log in to your store, our team can verify your account and discuss this situation with you in more detail via either live chat, email, or through a callback.
Since these steps should help resolve the troubles you're running into, I've marked my reply as the solution to your thread. This should help other merchants who may be experiencing issues with paying their bill, as it outlines the steps they can follow to reach a resolution, too.
Keep me posted on how this goes!
I wanted to follow up with you to confirm if you were able to contact us through our Help Center to discuss your invoice with our team?
Please let me know if you're still having troubles with this and I'll be happy to help out.