Upload AR PDF automatically to AR transactions for customers missing contact

We have requirement to archive the AR PDFs to avoid future changes to PDF due to master data updates or template changes. For that we want to preserve the PDF by attaching on the individual AR transactions. To achieve this, we are trying to attach the AR PDF to the AR transactions using AR_FEATURES to Upload Printed Receivables Transactions. However, it is failing when the contact and contact emails are missing.

We don't have customer contact for all Customers and due to this, its failing to attach the PDFs.

Please suggest how can we resolve this issue.