Join sales api with connect app - no matching id

For our support team I am trying to connect an atlassian-connect app with the appropriate sales api record (transaction and license) but it looks like there is no matching id.
the atlassian-connect app provides a cliendKey but it has nothing to do with License-id or Entitlement-id.

how to link the sales record with a cloud instance?

btw i did not find a better category for this - is there a sales-api topic somewhere?

cheers,
Florian