I was very concerned when I received your letter of yesterday complaining that the central heating system in your new house had not been completed by the date promised.
On referring to our earlier correspondence,I find that I had mistaken the date for completion. The fault is entirely mine and I deeply regret that it should have occurred.
I realize the inconvenience our oversight must be causing you and will do everything possible to avoid any further delay. I have already given instructions for the work to have priority and the engineers working on the job to be placed on overtime. These arrangements should see the installation completed by next weekend.
Yours faithfully
尊敬的先生/小姐，
昨天收到你的来信，抱怨你新家的中央加热系统未按规定时间装好，对此我非常关心。参考较早的通信，我发现我搞错了完成日期。错误完全是我的，对此我非常抱歉。
认识到我们的疏忽给你造成的不便，我们将竭尽全力避免再耽搁。我已指示这项工作优先做并让工程人员加班。这样安排会于下周完成安装。