Confirm purchase of a removed asset

[DivDCorwin]

A copyright holder of one of the images I licensed is reaching out for confirmation of license or they're going to charge us a fee for use. I can't see a record of it in license history, because the asset has been removed, and it was downloaded before my current earliest record listed. How do I go about obtaining proof?

[Abambo]

The licence stays in the licence history, even if the asset gets removed from the database. 

You may have used a different Adobe ID to license this asset.