I am truly sorry that_________________________(道歉的原因).
The reason is that_(介绍原因)
Once again, I am sorry for any inconvenience caused. Hope you can accept my apologies and understand my situation.
We have noticed a discrepancy between our invoice and the quantities you specified.
Thank you for your notice No. 1256. We are terribly sorry for the short delivery of our model A4521.
We have noticed a discrepancy between our invoice and the quantities you specified. On the quantities you required, we would ship the replacement at once. It is due to arrive at Hong Kong on September 30, and confirm by return that goods will be ready in time.
Let me reiterate our sincere regret regarding these problems. Thank you again for your proposal and your understanding of our position will be appreciated.
在調查貴公司所申訴的事件時，我們注意到敝公司發票上的數量與貴公司所需要的數量有不符之處。敝公司會針對貴公司所要求之數量，立即運送替代品。預計 於九月卅日 抵香港，並已收到確認回覆貨物將按時備妥。
Unfortunately, we regret your dissatisfaction with our product.
Thank you for your letter of September 30 in which you claim the wrong color of the hat. The matter has been given through consideration here.
Unfortunately, we regret your dissatisfaction with our product; our investigation does not support your claim. Consequently, we are not prepared to accept the returned hat and will have no alternative but to insist on payment of the contracted amount.
We would be happy to continue to cooperate in any way. And your courtesy will be appreciated, and we earnestly await your reply.
感謝 您九月卅日 信函所提有關帽子顏色不對的申訴，敝公司已做過全盤的考量。