Direct answer: Invoice payment follow-up should start from a confirmed invoice, schedule reminders against a clear policy and check the latest status immediately before each message. Paid, held, disputed, cancelled, stale or unconfirmed invoices must be suppressed. Every accepted, bounced or failed message remains in the invoice history without claiming inbox delivery.
Start from one confirmed invoice record
Import or create the invoice once, keep its customer and due date, and use a stable external reference to prevent a retry from creating a duplicate.
Check suppression immediately before sending
A scheduled reminder is not permission to send later regardless of status. Recheck payment, hold, dispute, cancellation, confirmation and consent state when the task runs.
Report mail status truthfully
Use queued, accepted by mail server, bounced or failed. Accepted by the mail server is not proof that the customer read or even received the message in the inbox.
Sources reviewed
These sources support the category wording or external method referenced above. SystemLineage’s workflow and limits are stated separately.
Review Invoice Payment Follow-up, then decide which records, limits and setup apply to your work.
See Invoice Payment Follow-up