Very sorry to have wasted your time so long, due to the risk of your company's orders too big for us, after careful consideration of our company, we decided not to take orders of your company
I am very sorry to delay you so long time, because your order risk for us is too big, after our careful consideration, we decided not to take your order
I'm sorry to delay you for such a long time. As the risk of your order is too great for us, after careful consideration of our company, we have decided not to accept your order