We regret that this misunderstanding has occurred
We regret that we are not in a position
We regret that we are unable to grant your request
We regret the necessity of calling your attention
We regret to be compelled for this reason to withdraw the privilege
We regret to learn that you are disappointed
We remain, dear sir, yours faithfully
We remain, gentlemen, with thanks
We shall await your early commands with interest
We shall await your reply with interest