For future reference, please post questions like this under the "Notebook" category. It is much easier to correct there, because there are options for highlighting, bolding, strikethrough, etc, that made corrections much more clear. Do you know why this P/O has been canceled suddenly? --> Perfect - From your feedback, we can see that we have lost some cases. Is our price too high? "Are our prices too high?" is probably better, but it depends on the products/service being offered, and if there are multiple, which there probably are, use the plural here. "Cases" is probably not the best word here, but without more context, I cannot suggest an alternative. In order to promote the probability of success, please let us know the reason. In order to increase the (perhaps "our" would be better than "the", but it depends on the context) likelihood of success, please let us know the reason. - Please keep tracking. If we really lose that order, it will be caused both of us a loss. Please continue tracking (I would add "this information", "this order", or "this package", depending on the situation). If we lose the order, it will cause a loss for both of us. - A quick, concrete reply would very much facilitate our procedures. A quick, concrete reply would very much facilitate our process.