✔ 最佳答案
Here is a sample of your letter with proper business practices.
We have noticed a discrepancy between the shipped quantity and the invoiced quantity in your invoice 123456 for the following items.
Item 1123, shipped 8, invoiced 10
Item 1189, shipped 9, invoiced 10
As we have paid the invoiced amount in full, please deduct the extra payment from the invoice of our next order.
Feel free to contact me if you have any questions.
Thank you.