Enroll button not buy button

We purchased this last year and have not yet used it in a complete web build, you helped us initially with some issues we had installing it on this site but we still have an issue and have not managed to use it since we purchased it.

When an event is set up, on the home page in the module you have the option to view 'DETAILS' or 'BUY' tickets. But if you view the event, you only have an enroll button visible which then add all three tickets to the user and the user doesn't get charged, they're free??