Clark, Ivy Greetings!
How does one make an enquiry about invoices, having disabled the subscription for fear of further charges?
A subscription can get disabled due to many reasons like your credit has expired, you reached your spending limit, have an overdue bill, hit your credit card limit, or because the Account Administrator cancelled the subscription.
I would suggest you, follow this documentation to Reactivate a disabled Azure subscription.
If you're unable to create a support request, try to reach support via global customer support.
Ensure to share your preferred contact method and account ID for the team to trace back and team will connect with you.
Once your subscription is active, You can always Create free Azure support request for billing to enquire about your invoices.
I hope this helps. Do let me know if you have any further queries.