1234, Main Street
Boston, MA 02123
03/17/05
<Recipient Address Goes Here>
Hello.
We regret that we must withhold payment of <reference invoice> until <conditions for payment>. <Elaborate on reasons.>
Until <conditions> we must continue to withhold payment. Upon satisfactory completion we will be happy to pay you in full.
Thank you for your prompt attention to this matter.
Regards,
Robert Anderson
encl: <List of enclosed items goes here>