在国际贸易中，及时有效的沟通对于维护良好的客户关系至关重要。尤其是在涉及款项支付的问题上，一封礼貌而专业的催款函能够帮助您更好地与客户保持联系，并推动交易顺利完成。以下是一封外贸英语函电催款函的范文，供您参考。

Subject: Follow-up on Outstanding Payment

Dear [Customer's Name],

I hope this message finds you well. I am writing to kindly follow up on the outstanding payment for the order number [Order Number]. As per our agreement, the payment was due on [Due Date], and we have not yet received it.

We value your business and appreciate the opportunity to work with you. However, to ensure smooth operations and maintain our financial stability, it is important that we receive the payment as agreed. Your prompt attention to this matter would be greatly appreciated.

If there are any issues or concerns regarding the payment, please do not hesitate to contact us immediately. We are more than willing to address any questions or resolve any discrepancies to facilitate a swift resolution.

Thank you for your understanding and cooperation. We look forward to continuing our successful partnership.

Warm regards,

[Your Full Name]

[Your Position]

[Your Company Name]

[Contact Information]

这封信件既表达了对客户的尊重，也清晰地说明了付款的重要性，同时提供了友好的合作意愿。通过这种方式，您可以有效地促进付款流程，同时维持良好的商业关系。希望这份模板能为您的外贸工作带来帮助！