In order for reports and transaction searches to work properly in PayJunction, User accounts cannot be deleted once they have been created. Instead, when a User is no longer employed by your business, the appropriate action is to edit the User and set it to INACTIVE. This will prevent any login through this User.
For instructions on editing a User account please see the following guide: How Do I Find Or Edit The Settings For Users?
Is there a limit to the number of Users I can add to my account?
No, you can add as many Users as you need for your existing and new employees.
Can I reuse a User instead of setting it to INACTIVE?
This is generally not recommended. In the event that the name and email address is changed on a User, PayJunction will be unable to distinguish for you whether an action was taken by the former employee or the new employee. In order to maintain accountability and accurate reporting it is almost always better to create a new User account.