If you are seeing the 'miscontactname', 'DATA NOT FOUND' error when viewing your communication please review the steps below -
If the pupil or payer information does not render when you produce your letters, you will need to ensure that you have the Priority information set to 'Normal' and the Send to option as 'Primary payer only : one message/child'.
If you are sending a letter to all parents, you will need to select the Priority as 'Normal' and the Send to option to 'All payers (primary and secondary)'.
However to ensure this works correctly you will also need to check that the letter template has the correct merge fields to pull through the additional parent account data through.
You can add this by editing the communication and using the merge fields of <consumerrepeater> to the beginning of your message/template and </consumerrepeater> to the end of your message/template.
You can see further information on the consumer repeater fields here -
How do I send a message to all parent accounts (primary and additional)?