B2B collections is not consumer collections. Your customer probably owes you because of a routing problem at their end, not malice.
- Lead with assumption of good faith. "We may have missed your payment confirmation" beats "your payment is overdue".
- Name the specific document. Invoice number, amount, due date. Vague messages get vague replies.
- Make the next step trivial. Payment link, billing contact email, current account statement attached. Friction lengthens DSO.
- Escalate by named human, not by tone. Stage 3 should come from the account manager, by name. Tone stays professional.
- Never threaten what you won't do. "Pre-legal" only at stage 4 with actual legal involvement. Empty threats train customers to ignore you.