The invoice settings has this option:
"Fail credit limit checks if there are overdue invoices, regardless of the credit limit amount. If ticked, any overdue invoices will cause a credit limit check to fail. If unticked, just the credit limit amount itself will be checked. Both options only apply to customers with a credit limit set up. "
I’d like that option to work regardless of the credit limit, so we can catch situations where a customer is ordering but has overdue invoice(s).