To see what a user spent their credits on:
Search for the user and navigate to the Credit Packs tab
Click on the pack you want see the usage for
On the right hand side of the screen you will see a list of all credits deducted.
Remember: Credits are only deducted if a user has either, Booked, Attended, Late Cancelled or No Showed a class. Regular cancellations are not shown as the credits used are returned.