商务知识：
催款有三个层次：
1．a friendly reminder
Example: I am writing to remind you that your bill for ￥5000 is now 30 days past due.
If you have any problem, we'll be willing to help. We would, however, appreciate hearing from you so we can work out a mutually agreeable payment schedule. Please use the enclosed envelope or call me at 12938434.
2. it's time to pay
Your account has been over due for 6 months. Considering your financial situations, which we realize have not been good recently, we have not pressed you for payment. By now, however, you should be able to make this long-delayed payment.
Please send your check in the enclosed envelope, or let us hear from you today to make a payment arrangement.
3. final warning -- legal action
You have not responded at all to our many attempts to collect the ￥9999 you have owed us since 31st july, 2006. Our next step is to take legal action to collect the money due us.
This is certainly unpleasant for both of us and is no doubt damaging to your credit rating. Therefore, we will delay any action for 7 days from the date of this letter. Please let us have your check on or before 31st December, 2006.
Whether or not we take legal action is now your decision.
If you have already sent your payment, please disregard this notice and accept our thanks for your payment.
这封信是写给客人的， 无论如何要客气 就算是final warning.
2-1-3
Dear Hong:
We would like to call your attention that your balance of $8500 is past due on 4th of May this year, which was 6 months ago. We will greatly appreciate your prompt