Change overdue invoice emails from misleading subject "you paid an invoice"

[protohaven]

Currently, automatic overdue invoice emails are being sent to customers with the email subject "you paid an invoice" even if the invoice is overdue and unpaid. This is very confusing to customers because it leads them to believe their invoice has been paid, even if it failed and is overdue. There is no way to change the contents of automatic overdue emails without disabling them entirely. This is inhibiting us from getting paid in a timely way.