Go to your Workspace and click on the button: "My Sells" the list of your sales/customers will be displayed in order from the most recent to the oldest.

For a specific search click on the "Buyer Finder" button or insert the user's id64 in the "search" location (see 1 in the image below)

You will be able to obtain information such as the date of purchase, the latest version downloaded and whether the product has already been downloaded by the customer.