We are very sorry to notice you that the package is probably lost.We have sent the package on April 28, and the tracking information is still not available online yet. We contacted with the post-office and we are waiting for their response (reply).We understand your frustration, and try to settle down this situation(/I am handling this situation). Thank you for your patience. We will keep you informed. Best regards, 注意: 1. possibly: <10% 的可能性,probably: 50%的可能性。 2. 日期用 on 不用 at 3. 因为已经联系了邮局,正在等待回信,所以用 contacted 而没有用 tried to 一般 try to 试着做,但还没有做到。4. 不要用 We know that it really sucks! 这是口语用法,而且可能让客户觉得你sucks, 因为这样说你是站在第3方立场(幸灾乐祸?),你应该把自己和客户放在同一条船上。 应该用 我们理解您的失望。正在努力处理该情况。谢谢您的耐心。我们会及时通知您事情的进展:We understand your frustration, and try to settle down this situation (I am handling this situation). Thank you for your patience. We will keep you informed. 这么说了千万别忘了有了进展通知人家。